ISH 163 
M 

11904 
Copy 1 



U. S. COMMISSION OF FISH AND FISHERIES, 
GEORGE M. BOWERS, Commissioner. 



o22 



ARTIFICIAL PROPAGATION 



OF 



MAEINE SPECIES 



Extracted from the Eevised Edition of the Fish Manual. 
Pages 195 to 238, Plates 54 to 63. 



WASHINGTON: 

GOVERNMENT PRINTING OFFICE. 

1904- 




Class S H \ b 3 
Book . r^"^ 



VC^ D^ 



U. S. COMMISSION OF FISH AND FISHERIES. 

GEORGE M. BOWERS, Commissioner. 

522 



ARTIFICIAL PROPAGATION 



OF 



MAEINE SPECIES 



Extracted from the Revised Edition of the Fish Manual. 
Pages 195 to 238, Plates 54 to 63. 



WASHINGTON: 

GOVERNMENT PRINTING OFFICE. 
1904- 



D. OF Ofc 

MAY 7 1908 



Fish Manual. i,To face page 1 95.) 



«!!&- M. '■^'jm 



Plate 54. 



'^^3. 



^ . '!//■{'■/ 






' ^^*ii 



' ./ 




THE COD. 



DESCRIPTION OF THE FISH. 



The body of the cod is moderately long, compressed and tapering 
behind; the greatest depth is about one-fourth its length. The large 
head is narrowed anteriorly and is contained 3i to 4^ times iu the 
body length. The mouth is large; the lower jaw is included within 
the upper when the mouth is closed; the maxillary extends to about 
middle of eye. The diameter of the eye is about half the length of the 
snout and one-fifth that of the head. There is a conspicuous barbel on 
the chin. The number of dorsal fins is 3 and of anal fins 2; the 
dorsal rays are usually about 14, 21, and 19 in the respective fins, and 
the anal rays are 20 and 18. ' The ventral fins are well developed, with 
about 7 rays. The cycloid scales, with which the body is covered, are 
very small. The air-bladder is large and thick. The color varies 
greatly, depending on food, kind of bottom on which found, and other 
conditions. Fish taken offshore in deej) water are usually olivaceous 
on the back and whitish beneath ; the so-called rock cod, found in shoaler 
water among rocks and kelp, vary in color from green to deep red. The 
back and sides are covered with small, round, reddish-brown spots. 
The lateral line is conspicuous, of a whitish color. The fins are dark. 

From other si^ecies of the lamily, taken in the same waters, the cod 
is readily distinguished. From the haddock it differs in having a pale, 
instead of a black, lateral line; in its spots (absent in the haddock), 
and in its larger maxillary bone, which reaches past the eye, while in 
the haddock this bone does not extend to the eye. The features dis- 
tiuguishiiig the pollock from the cod are the smaller size, the projecting 
lower jaw, the uniform coloration above, the sharp snout, the smaller 
barbel, etc. The hakes have only 1 anal and 2 dorsal fins, a filamentous 
prolongation of the first dorsal ray, and a ventral fin consisting of two 
or three very long filamentous rays. 

The status of the cod of the North Pacific Ocean is somewhat uncer- 
tain. It has generally been considered identical with the Atlantic 
species, but its smaller air-bladder and other features may entitle it to 
recognition as a distinct species. 

RANGE, MOVEMENTS, FOOD, ETC. 

Cod are widely distributed in the North Atlantic Ocean. To the 
north they range far beyond the Arctic Circle, and to the south as far 
as Cape Hatteras, although they are not common south of New Jersey. 

195 



196 REPORT OF COMMISSIONER OF FISH AND FISHERIES. 

The cod of the ISTorth Pacific Oceau is found from Bering Sea south to 
Oregon and Japan. 

The movements of cod are not well understood. They go in schools, 
but iu much less dense bodies than do mackerel, herring, and men- 
haden, and when moving from one ground to another they are in more 
compact schools than when ou the feeding-grounds The movements 
on and off shore and from bank to bank are due to several causes, 
among which are the effects of water temperature, the presence or 
absence of food, and the sj^awning instinct. In the winter months 
there is a well-marked movement of large bodies of codfish to the 
shores of the New England and Middle States, and important fisheries 
are there carried ou in regions from which cod are absent at other 
times. This movement seems to be chiefly for the purpose of finding 
shallow grounds for spawning. That the cod sometimes makes very 
long journeys is shown by their capture on the New England coast 
with peculiar hooks in their bodies which have been identified as 
similar to the hooks employed by the French cod fishermen on the 
Grand Banks. 

Although sometimes found in shallow water, cod are essentially deep- 
water fish, preferring water from 20 to 70 fathoms deep and being 
found even at a depth of 300 fathoms. Those caught for market are 
usually taken at depths of 20 to 40 fathoms. 

The cod takes its food on the bottom, at the surface, or at intermediate 
points. It is an omnivorous and extremely voracious feeder, consuming 
all marine animals of suitable size. Favorite articles are bivalve 
mollusks, crabs, lobsters, starfish, and fish. Among the fish consumed 
in large quantities are capelin, lant, herring, alewives, menhaden, 
mackerel, and haddock, although many others are also eaten. The 
abundance and movements of such fish have an important relation to 
the presence and abundance of cod in a given region. 

WEIGHT AND GROWTH OF COD. 

The largest cod recorded from New England waters weighed 211i 
pounds and was over 6 feet long; it was taken on a trawl off the 
northern Massachusetts coast in May, 1895. The capture of a number 
weighing from 100 to 175 pounds could be cited, but those exceeding 100 
pounds in weight are by no means common, and even 75-pound cod are 
not numerous. The average weight of the larger-size cod caught in the 
shore waters of New England is about 35 pounds; on Georges Bank, 
25 pounds; on the Grand Banks and other eastern grounds, 20 pounds; 
the average weight of the small-size fish caught on all these grounds is 
about 12 pounds. 

Observations in Massachusetts of the rate of growth of the cod show 
that those 1^ to 3 inches long are about 6 months old ; those 9 to 13 
inches long, and weighing 7 or 8 ounces, are li years old ; those 18 inches 
long, and weighing 2 to 2^ pounds, are 2i years old; and those about 22 
inches long, and having a weight of 4 to 5 pounds, are 3^ years old. 



MANUAL OF FISH-CULTURE. 197 



SPAWNING. 



The principal spawning time of the cod on the New England coast 
is winter, but the season begins as early as November and continues 
until April. Spawning fish are occasionally caught from October until 
May. The spawning period for an individual fish is greatly prolonged, 
and probably covers six or eight weeks, only a small percentage of the 
eggs maturing at one time. The male and female cod may attain 
sexual maturity when weighing only 3 J or 4 pounds. The ages of 
normal fish having these weights are supposed to be three to four 
years. 

When imiDelled by the spawning instinct, the cod seek the shoal 
waters of the coast or banks in schools consisting of both sexes. The 
female is less active than the male at this period, and probably rests 
quietly on the bottom while discharging the eggs. There is no evidence 
to show that the sexes are paired or in close proximity during the act 
of spawning. On the contrary, it seems likely that fertilization is 
generally accomplished by accidental contact of the sexual products 
as they are swept about by the elements, having risen to or near the 
surface as soon as extruded. 

The cod is one of the most prolific fishes. The ovaries of a 21-pound 
fish have been computed to contain 2,700,000 eggs, and a 75-pound cod 
has been estimated to have 9,100,000 eggs, these figures being deduced 
by careful weighing or measuring of a known number of eggs. The 
egg is from -fg to -jV inch in diameter, the smallest fishes having the 
smallest eggs; the average size may be taken as ^V inch. The approxi- 
mate number in a fluid quart is 337,000. 

The destruction of cod eggs in nature is necessarily large. The 
principal loss is probably through failure of iminegnation, the eggs 
losing their ability to become fertilized and the milt its vitality very 
soon after being thrown from the fish. Incalculable numbers are thrown 
on the shore by the waves and there die. Cod eggs are also destroyed 
by numerous animals, including fish, birds, and invertebrates. 

COMMERCIAL IMPORTANCE AND POOD VALUE. 

The cod is one of the most valuable of all food-fishes, and in the 
United States ranks as the most prominent commercial fish. In the 
matter of persons engaged, vessels employed, capital invested, and 
value of catch, the taking of cod in the United States is more extensive 
than any other fishery for fish proper.* The number of vessels which 
fish wholly for cod or take cod in noteworthy quantities, together with 
other "ground fish," is not less than 600, of over 25,000 net tons burden, 
carrying about 7,000 men, and with a value of $3,000,000, besides which 
there- are very large fisheries carried on from boats and small vessels 
of less than 5 tons burden. The approximate annual value of the cod 

* The oyster fishery is the most imjiortant branch of the fishing industry of the 
United States. 



198 REPORT OF COMMISSIONER OP PISH AND FISHERIES. 

catch in 1898 was about $2,000,000, a sum representing the first value 
of the fish. The weight of the fish as landed from the vessels (fresh, 
split, and salted) was about 96,000,000 pounds. 

The cod fishery is prosecuted in all the coastal States from Maine 
to New Jersey, being most important in Massachusetts and Maine. 
Gloucester and Boston are the principal fishing centers. On the 
Pacific coast there is an important fishery in Alaska, carried on by San 
Francisco vessels. 

Cod are taken with hand and trawl lines, baited with fish, squid, etc., 
and fished from small boats or the vessel's deck. The principal grounds 
in the Atlantic are the famous "banks" — Grand, Georges, Western, 
Quereau, etc.; on the Pacific coast the Shumagin Islands are the chief 
grounds. Small quantities are taken in traps at places on the New 
England shore. 

ARTIFICIAL PROPAGATION. 

The cod is propagated artificially on a more extensive scale than 
any other marine fish. Artificial hatching was first undertaken at 
Gloucester, Massachusetts, in the winter of 1878-79, and has since been 
regularly i^rosecuted on an increasingly large scale at both Gloucester 
and Woods Hole. Up to and including the season of 1896-97, the 
number of cod fry liberated by the Commission on the east coast was 
449,764,000. The output of fry in the last-named year was 98,000,000. 
The unmistakable economic results which have attended these efforts 
warrant all the time and money devoted to them and justify the greatest 
possible expansion of the work. 

COLLECTING EGGS ON THE FISHING-GROUNDS. 

The following methods are pursued in collecting cod eggs for the 
United States Fish Commission station at Gloucester. 

As cod are abundant in Ipswich Bay during the winter, vessels from 
Gloucester, varying in size from 10 to 70 tons, engage in fishing there, 
starting from Kittery Point, Maine, or Portsmouth, New Hampshire, 
where they market their catch, secure bait, and obtain supplies. At 
the beginning of the cod season (which usually opens from the middle 
to the last of November) arrangements for the board of the men, dory 
and building hire, transportation of eggs, etc., are made with persons 
at Kittery Point and permission to place spawn-takers aboard the 
fishing vessels is obtained, with the understanding that they will be 
allowed to take eggs from the fish secured, that they be given the 
freedom of the vessel in order to properly care for the eggs, and that 
no charges be made against the Commission except that 25 cents be 
paid for each meal furnished the sjiawn-takers. After these arrange- 
ments are made the men are directed to board such of the fleet as are 
at the time meeting with the best fishing, but as the fish are not of 
uniform abundance in the bay it is necessary to keep a vigilant watch 
on each vessel's catch as it is landed, daily, to know where to place 
the spawn- takers to the best advantage. 



1 



Fish Manual. (To face page 193.) 



Plate 55. 




MANUAL OF FISH-CULTURE. 199 

A spawu-taker's outfit consists of a water bucket or pail, a dipper, a 
siphon, a thermometer, and a tin spawn-kettle about 2 feet long, 1 foot 
wide, and 8 to 9 inches deep; the kettle has a cover and handle. 

When new spawn-takers are employed they are instructed in the 
work and sent out in vessels with the experienced men to familiarize 
themselves with the methods. The spawn-takers ordinarily leave their 
boarding-places at 1 o'clock in the morning (though the time varies 
somewhat, according to the weather) and join the boats anchored in the 
harbor of Kittery or at Portsmouth. During moderate weather the men 
frequently go aboard before midnight, as the vessels must sail when 
the tide is favorable, to avoid getting becalmed or meeting a head tide, 
either of which might prevent them from reaching the fishing- grounds 
in good season. 

After joining the vessels, the spawn- takers usually assist the fisher- 
men in getting under way, managing the ship, etc., and on reaching the 
place where the nets or trawls are set — usually 6 to .10 miles distant — 
the spawn-takers help the crews in hoisting out and dropping the dories 
on the gear as each buoy is reached, the men remaining on the vessel's 
deck with the captain while the fishermen are hauling or under-running 
their gear, and until they return to the vessel with the fish. 

As soon as the dories begin to arrive with fish, the work of the spawn- 
taker begins. As the fish are pitched aboard, the spawn-taker stands 
ready to examine each one and select those that may contain ripe eggs 
or milt. As the dories are usually picked up in the same order in which 
they are dropped, there is opportunity to strip the fish without much 
hurry, but sometimes several are picked up in a short space of time, 
and if a large quantity of fish is landed the catch remains on deck 
until the spawn-taker can overhaul it. In bad weather, however, when 
the fish would be in danger of being washed away, they are put in bins 
on deck and can be pitched from one bin to another by the si3awu- 
taker as the condition of each is determined. Usually one of the crew 
assists in this work and often renders valuable assistance. Great care 
is taken not to get any green or dead eggs with the good ones and to 
keep the eggs as free from foreign matter as possible; but in rough 
weather, when the vessel is j)itching or rolling heavily, vigilance in 
these respects is necessarily somewhat relaxed. 

The spawn-taker seizes the fish by the tail, places the head under the 
left arm, if it is not too large, leaving the right arm free for stripping 
the fish, which is done in the usual way. Only live fish or fish recently 
dead are used. 

The eggs are first taken in a common pail, the inside of which has 
been moistened with water. Then a sufficient quantity of milt to 
fertilize the eggs is added and thoroughly mixed with them and allowed 
to remain from 10 to 20 minutes, or longer, after which water is added 
and the eggs are carefully cleaned by siphoning off the old water 
and putting in fresh water until all the slime and milt are drawn from 
the x)ail. The good eggs, which rise to the surface of the water, are 



200 REPORT OF COMMISSIONER OF FISH AND FISHERIES. 

then transferred to the spawn-kettle containing clean water and the 
poor or dead eggs are thrown away. 

All the eggs obtained on a given vessel are kept in the kettle until 
the receiving-house on shore is reached, the water on the eggs being 
changed at intervals during the passage in; and to keep the tempera- 
ture uniform, the eggs are shifted from one part of the vessel to 
another, according to conditions. Sometimes, when the sea is very 
choppy or rough, the pail can not safely be used, as the eggs will spill 
out, and they are then stripped directly in the spawn-kettle and cleaned 
as well as possible. 

It was formerly the practice to take cod eggs in a small quantity of 
water, but during the season of 189G-97 it was determined to test the 
relative efficacy of the so-called wet and dry methods of fertilization. 
Some of the spawn-takers were instructed to emi)loy the dry method 
and others the wet method. The experiments show that when eggs 
were taken by the dry method a much larger percentage was fertilized 
than when taken in water. Eggs from fish caught on trawl lines inva- 
riably yield a larger percentage of fry than those from fish caught in 
nets, although fine eggs are frequently obtained from net fish. The 
explanation seems to be that fish caught in nets soon become entangled 
and are either drowned, or nearly so, shortly after being meshed; they 
struggle a great deal more than fish on trawls and the greater part of 
them are dead when taken into the boats, many of them being scaled, 
which indicates severe exertion in trying to escape. Trawl fish, on the 
other hand, are almost always alive and active when taken from the 
water, and very few fish without scales are found unless the gear has 
been out a long time or has been set during a heavy storm, when, of 
course, many of the fish will be dead. 

Better results are obtained from eggs taken when the weather is 
fairly cold than when it is warm, as when the temi)erature is high it is 
difficult for spawn-takers to keep the water containing the eggs at a 
safe temiDcrature, and before the egg house on shore is reached there is 
almost always a heavy loss. When the weather is too cold for eggs to 
be kept on the vessel's deck the spawn-takers put them below the deck, 
where the temperature will be suitable. 

Many difficulties and much exposure are encountered by the men 
who collect cod eggs on the fishing vessels, and during severely cold 
and windy weather, when the deck is covered with ice and the fish 
freeze stiff in the dories before they reach the vessel, it is practically 
impossible to get good eggs. During boisterous weather, when the 
fleet succeeds in hauling the gear only once or twice a week, the greater 
part of the catch is generally dead when taken. A spawn-taker often 
secures a good lot of eggs and can find no ripe milt fish, but in this 
event he will, if the weather i^ermits, visit the nearest vessel in quest 
of milt. Sometimes there is a school of milt fish in the bay and very 
few female fish, and a vessel may catch several thousand pounds of cod 
day after day without finding ripe spawn in any of them, while another 



Fish Manual. (To face page 200.) 



Plate 56. 



IP 



PI' 






MANUAL OF FISH-CULTURE. 201 

vessel, fishing only a short distance away and not catching many fish, 
will get a comparatively large number of si^awners. 

The spawn-takers are instructed not to take eggs from fish that have 
died on trawls or in nets, although fine lots of eggs are often taken from 
fish that die in the dories before they reach the vessel, showing that the 
eggs do not die immediately after the fish expire. The vitality of the 
eggs after the death of the fish varies in different cases and dei^ends on 
the conditions of the eggs and the fish at the time the fish are caught, 
the state of the weather, etc. An experienced spawn-taker can almost 
always distinguish readily between good and poor eggs, although it is 
not always possible to determine whether or not a given lot of eggs will 
live. As the weather and the nature of the school of fish in the bay 
regulate the collection of eggs, the results of a season's work can not be 
estimated in advance. It has been observed that roe fish are found in 
largest numbers previous to an easterly storm and when the wind is 
from the south or west. During heavy westerly winds cod appear to 
approach quite close to the beach, and when the wind blows from the 
eastward and the sea begins to rise, they leave for deeper water. 

When fishermen are hauling their nets and trawls, they frequently 
notice spawn being emitted from fish when they are landed in the 
dories. Such fish are laid away on their backs in the stern of the boat 
and when the vessel is reached are carefully passed to the spawn-taker, 
many eggs that would otherwise be lost being thus saved. 

When the price of fish is low at Portsmouth or the wind is unfavor- 
able for making that harbor, some of the fleet go to Eockport to sell 
their fish, and should spawn -takers be on such vessels they immediately 
take their eggs to Gloucester when the vessels arrive in Kockport. 

Usually the fishing vessels return to Kittery Point between 1 o'clock 
and 10 o'clock p. m. Immediately on landing, the spawn-takers carry 
their collections to the egg-house on shore, where the spawn is carefully 
examined, cleaned, packed, and shipped' to Gloucester by first train. 
In shipping eggs large fruit jars are used. About 350,000 eggs are put 
in each jar, the jar is filled with water, the top is securely fastened, 
and the jar is placed horizontally in a large iron kettle made especially 
for the purpose and holding five jars. The jars are wrapped in burlap 
before they are put in the kettles, to prevent them from breaking, and, 
when necessary, snow or ice is put in each end of the kettles to keep 
the temperature uniform during transit, but it is not allowed to come 
in direct contact with the jars. 

A messenger usually accompanies the eggs and gives them constant 
attention until they are delivered at the station. The snow or ice is 
removed from the kettles, if the temperature falls too low, and replaced, 
if necessary, the messenger making frequent use of a thermometer. 

In preparing eggs for shipment without messenger, they are first 
cleaned carefully by drawing off all dead eggs or dirt, then put in large 
fruit jars in the same manner as when they are shipped to Gloucester, 
and the jars are packed horizontally in large wooden cases holding nine 



202 REPORT OF COMMISSIONER OF FISH AND FISHERIES. 

jars each. Eockweed or moss, together with ice or snow, is used in 
packing- them, the former being placed around the jars and the latter 
put in the bottom, sides, and top of the case to keep the eggs cool. 
Successful shipments are often made by express. 

Some difficulty has been experienced in keeping large lots of eggs 
over night at Kittery Point, as the facilities are insufficient for chang- 
ing water or for spreading the eggs out to overcome the injurious effects 
of prolonged crowding; but when it is uecessaly to so retain them, they 
are put in McDonald jars in which the water is changed as often as the 
supply will permit. As the water in the harbor is partly fresh and 
unfit for this puriiose, it is necessary for spawn-takers to bring in a 
supply from the open bay in large transportation cans. 

CAPTURING AND PENNING BROOD COD. 

Practically all of the cod fry hatched at Woods Hole i^rior to 1896 
represented eggs taken from penned fish. Some of the cod collected 
for breeders are caught by the crew of the Fish Commission schooner 
Grampus and some are purchased from commercial fishermen. Two 
or more smacks usually engage in fishing for the station during the 
collecting season, which is from about October 1 to November 30. The 
grounds resorted to are east of Nantucket and around Block Island. 
The fish are taken with hand lines fished from the deck while the vessel 
is drifting, in water from 10 to 40 fathoms deep. Those taken in the 
shoaler water are preferable to those coming from deep water, as the 
change to the shallow cars in which they are held at the station is less 
pronounced. Great care is exercised in catching the fish, for when 
hastily hauled up from deep water they are very liable to be " poke- 
blown," that is, they have their stomachs turned inside out through the 
mouth. When drawn in with moderate speed, they become adapted to 
the gradually diminishing pressure and do not suffer injury. It is also 
imi)ortant in unhooking the fish not to injure its mouth any more than 
is absolutely necessary, as the wound caused by the hook frequently 
spreads and forms a large sore and eventually kills the fish. All the 
vessels which collect cod for the station are provided with wells in which 
the fish are placed and held while in transit. 

When a vessel arrives at the station with cod, the fish are immedi- 
ately transferred with dip nets from the well to live-cars 16 feet long, 
6 feet wide, and 5 feet deep, which are constructed of wood and divided 
into two compartments by a crosswise partition. As the fish obtained 
from smacks are paid for by the pound, it is customary to weigh about 
10 per cent of each load and estimate the total weight by the average 
of those weighed. While being weighed, the cod are also counted, 
about 500 being put in each car. The cars are moored in the middle 
of a pool or basin protected on all sides by a wharf, which breaks the 
force of the sea in stormy weather and aflbrds a sheltered place for 
handling the fish and taking the eggs. 

Cod take little or no food when spawning. The impounded brood 
fish are often tempted with fresh fish and with fresh and salted clams, 



MANUAL OF FISH-CULTURE. 203 

but tliey can rarely be induced to eat. A certain percentage of tbe 
penned fish die and are removed at once from tlie cars. The develop- 
ment of the sexual organs is noted when the dead fish are taken out. 
Fish about ready to spawn are placed in a separate car and carefully 
watched. They are examined two or three times a week and any ripe 
eggs are taken. 

In takiug and fertilizing the eggs of brood cod the same general 
methods are followed as are adopted on the fishing vessels in Ii)swich 
Bay. The spawn-taker grasps the ripe fish near the tail with his left 
hand and holds the fish's head either between his body and left arm or 
between his thighs, using his right hand to strip the fish. The eggs 
are usually taken in a bucket. Both the dry and wet methods of fertil- 
ization are used at Woods Hole. Usually about 80 per cent of the eggs 
taken are fertilized. Unlike many other fishes artificially propagated, 
the cod does not yield all" of its eggs at one time. After expressing all 
the eggs possible from a given fish, it is returned to the live-car, and in 
a few days will have matured more eggs, which are then taken. When 
the ovaries have discharged all their eggs, the fish is released. 

In recent years from 1,600 to 9,000 cod have been penned annually 
in the protected basin at Woods Hole. Only from one-ninth to one- 
third of these, according to the season, yield good eggs. 

CHARACTERISTICS OF COD EGGS. 

Cod eggs are nearly transparent, and float at the surface of the water 
when first taken. They vary in color from a j)ale green to a deep red, 
those having the green color being the best. Good results are seldom 
obtained from the red eggs, and those of a deep red color almost invari- 
ably die in three or four days after being received. Unless the density 
of the water is low, the eggs normally float during the entire hatching- 
period. However, it frequently happens that, owing probably to the 
accumulation of sediment, the eggs gradually sink during the last third 
of the incubation period, and finally mass together on the bottom of the 
hatching-box ; here they would quickly smother but for the current. 

Floating eggs are not necessarily good ones, for unfertilized and 
injured eggs usually float IS to 36 hours before going to the bottom. 
Unfertilized eggs may be readily detected, as they have no disc which 
marks fertilization and have a milky appearance. Th»e dead eggs 
quickly sink, and are easily distinguished from the sound eg^s by a 
white spot in the center. 

Eggs received at the hatchery are transferred from the vessels in 
which they came to Chester jars partly filled with water, and in 10 
or 15 minutes they rise to the surface in a dense mass. The eggs are 
put in each jar to the depth of an inch, a quantity representing approx- . 
imately 379,000 eggs. If the hatchery is full, about a fifth more eggs 
may be put in a box, the maximum number that may be safely carried 
being 450,000. The first measurements are carefully made, as they form 
the basis for subsequent estimates. As soon as the eggs are measured 
they are transferred to the hatching-boxes with dippers. 



204 REPORT OF COMMISSIONER OF FISH AND FISHERIES. 



THE APPARATUS USED IN HATCHING COD. 

The apparatus and methods employed in cod-culture are the out- 
growth of long' experience and study and have as their special features 
the closest possible simulation of natural conditions. The apparatus 
now in general use is the so-called McDonald or automatic tidal box. 
The boxes are constructed in series of 12 or less, the number depend- 







PLAN. 


» / 








f=4 




1 


o 


/ 


\ 




HI 


/ 






' H — M-. 

A — ^-4 


1 


1 


o 


/ " ^ >. 


c 


\ / 




■ H 



Secfion through A-B 





Diagram of Tidal Cod Hatching-Box. 



«, partition foriuiug space at lower eud of 

compartment. 
/, glass gate. 
(/, slot between adjoining compartments. 



A-B Points where cross-section is taken, 
a, siphon. 

c, partitions forming upper pockets, 
rf, partition forming space at tipper end of 
compartment. 

ing on the size of the hatching-room, the arrangement of the hatching- 
tables, or other conditions. The Gloucester hatchery has 8 tables of 
9 boxes each, and Woods Hole 14 tables of 12 each. At Gloucester 
25,000,000 eggs can be hatched at one time, and at Woods Hole 
65,000,000. For a wooden framework to accommodate 9 boxes such 
as are used at Gloucester the outside dimensions are: Length, 10 



Fish Manual. (To face page 204.) 



Plate 57. 




MANUAL OF FISH-CULTURE. 205 

feet; width, 3 feet 8 inches; depth, 11 inches. The table or trough is 
constructed of 2-inch lumber and raised to a convenient height by 
short, stout legs. The table is divided into 9 water-tight compart- 
ments by means of crosswise ]:»artitions of 1^-inch plank. 

At Woods Hole the dimensions of the troughs containing 12 boxes 
are as follows: Length over all, 13 feet; width, 2 feet 7 inches; depth, 
12 inches. The plank is li inches thick. The bottom of the trough is 
2^ feet above the floor. The compartments are separated by 1^-inch 
partitions and are 22 inches long, 12 inches wide, and lOf or 11 
inches deep. 

Two inches from each end of each compartment there is a 1-inch 
wood partition. The partition d at the supply or upper end of the 
compartment extends with its middle portion to the bottom of the 
trough, while the two sides extend only to within 1^ inches of the bot- 
tom. The partition e, at the discharge or lower end of the compart- 
ment, extends its full length to within Ih inches of the bottom of the 
trough. Between the two partitions d and e in each compartment there 
is snugly fitted a movable box in which the eggs are placed. This 
box, which is constructed of i-inch plank, is 9 to 9J inches deep in the 
center, but only 8 inches deep at the corners, the bottom sloping 
upward toward the sides and ends of the box and being covered with 
linen scrim. A wooden strip at the bottom, ^ inch thick and conform- 
ing to the shape of the bottom of the box, extends the length of the box. 
The box rests on cleats in the corners of the compartments which keep 
the center of the box li inches above the bottom of the trough. 

The space at the supply end of each compartment is divided into 
three pockets by 1-inch wood partitions. The middle pocket connects 
with the main compartment by means of a small hole {-^^ to -^ inch) 
through the center of the partition and end of the box immediately 
above the lengthwise strip, and the two lateral pockets connect by a 
space at the bottom with the main compartment. 

At Woods Hole the water used in hatching is pumped from the 
harbor to two tanks of about 18,000 gallons joint capacity. The water 
is led to the hatching-room through a 4-inch wooden pipe and is sup- 
plied to the hatching apparatus through a 2^-inch hard-rubber pipe 
which branches from the main pipe and runs directly over each row of 
tables. At Gloucester the main supply-pipe is of hard rubber, 3 inches 
in diameter; this leads from a tank of 15,000 gallons capacity, the 
bottom of which is about 6 feet above the level of the troughs. A small 
soft-rubber tube, provided with a rubber pet-cock, carries the water to 
the middle pocket at the back of each box. As the pocket is always 
full of water when the boxes are in operation, a considerable amount 
of water goes through the small hole with much force, creating a strong 
current in the box and keeping the eggs in constant rotary motion. 
This current is one of the principal features of the apparatus. 

Much more water enters the middle pocket than Can pass through 
the small hole into the box, and the surplus flows over the sides and 



206 REPORT OF COMMISSIONER OF FISH AND FISHERIES. 

enters the main compartment from below, coming np through the scrim 
covered bottom into the movable box. 

The partition forming the pocket at the lower or front end of the box 
only extends to within 1^ inches of the bottom, leaving a space 
through which the water runs from the compartment. In the bottom 
of the i)ocket there is an opening in which the vertical waste-pipe fits. 
This pipe is brass, i inch in diameter and 10 or 11 inches long; the top 
of the pipe is 7 inches above the bottom of the table. The waste-pipes 
from the different boxes discharge into a trough which carries the water 
from the building. 

A particularly important part, and the one which gives the name 
"tidal box" to the apparatus, is used in conjunction with the waste- 
pipe. This is a brass siphon-cap, which fits over the upper end of the 
waste pipe. The cap is a tube, closed at the top, 9 inches long and IJ 
inches in diameter. It is kept at any desired height on the waste-pipe 
by wire springs in the cap or by other means. 

By virtue of the siphon attachment the water in each box rises to 
the height of the top of the waste-pipe and begins to run over. This 
partly exhausts the air in the cap, more water rushes in, and the pipe 
becomes filled with water ; then the siphon begins to act and takes off 
the water to a level of the bottom of the siphon-cap. Usually the caj> 
is i)ushed about half down the waste-tube, although the height of the 
water in the box after the discharge ot the siphon is regulated by the 
manner in which the eggs are working. About 7 minutes are required 
for the water to be drawn down and the box to again fill, and approxi- 
mately two-fifths of the water is taken off at each discharge. By this 
arrangement; the water in the boxes is constantly rising and falling 
automatically; the movements of the waves are thus simulated, the 
eggs are kept in constant circulation, and fresh water is continually 
entering the boxes. 

The Chester box was generally used in cod-culture up to a com- 
paratively recent date, and is still occasionally employed in marine 
fish-cultural operations. The general object of its construction is the 
production of an automatic rise and fall of water, as in the McDonald 
box, although it differs from the latter in some essential particulars. 
It consists of a box of variable dimensions in which jars are placed for 
the reception of the eggs. A convenient size of box is 7i feet long, 2 
feet wide, and 2^ feet deep. From 4 to 8 large glass jars are arranged 
on wooden supports 7 or 8 inches above the bottom of the trough. 
Smaller boxes, to accommodate only 2 or 4 jars, are also used. The jars 
are about 9 inches in diameter and are of two heights — 9 inches and 17 
or 18 inches ; they have straight sides and a flat bottom with a central 
half-inch hole. 

The jar is placed in the box in an inverted position, with its bottom 
above the level of the top of the trough. The sea water supplying the 
trough enters the compartment at one end of the trough and escapes 



Fish Manual. l^To face page 206, 



Plate 58. 




CHESTER BOXES. 



MANUAL OF FISH -CULTURE. 207 

by means of a siphon in the other compartment, running through a hole 
several inches below the top of the trough. The trough fills with water 
up to a level with the hole, when the siphon begins to act and takes off 
the water more rapidly than it enters, to a level with the inner end of 
the siphon, the fall being 4 to 5 inches. Air then enters the siphon, 
and it ceases to act until the water has again risen to the height of the 
discharge hole. The water thus rises and falls in the jars automatically, 
the interval between the successive discharges being regulated by the 
length of the inner arm of the siphon, the size of the tube, and amount 
of water supplied. 

After the eggs are introduced into the jars a piece of cheese-cloth or 
linen scrim is placed over the top, and fastened by means of rubber 
bands. The jar is then inverted and placed on the wooden supports 
provided for the purpose, and the plug in the bottom removed to allow 
the escape of the air and the rise and fall of water. The number of 
eggs per jar is about 190,000 or 200,000. 

DEVELOPMENT OF THE EGG. 

The development of the cod egg is greatly influenced by the water 
temi)erature, which fluctuates from day to day and makes it difHcult to 
state exactly when the eggs will hatch. With a high temperature the 
advancement of the egg through the different stages proceeds rapidly 
and can readily be appreciated with the unaided eye, while with a low 
temiierature the development is slow and may be greatly iirolonged 
by very cold water. With a mean temperature of 47° cod eggs begin 
to hatch in 11 days, although 2 or 3 additional days are usually nec- 
essary for all the eggs of a given lot to hatch. At 13° the time is 14 
or 15 days, and at 38° it is 20 to 23 days. The best results are obtained 
when the temperature ranges from 41° to 47°. The hatching proceeds 
satisfactorily with the water at 38°, but with a lower temperature 
the incubation period is so long that the fry are very weak. On the 
natural spawning-grounds the water seldom gets below 38°, while at 
the stations after January 1 the water used for hatching rarely gets 
as warm as 37°, and often is as low as 31°; from the middle of January 
to the latter part of February it remains at about 32°. Since it is 
impossible to do even fair work when the water gets below 35°, it has 
been the practice to warm the water by passing it through a coil of pipe 
contained in a tank of warm water or by introducing steam directly 
into the water pipe whenever the hatchery water gets below 37°. • 

The water being at 47°, during the first 4 days the egg passes 
through the different stages of segmentation ; at the end of that time 
the germinal area begins to assume the general form of a fish; and by 
the ninth day the fish is quite well formed, and may be readily seen 
with the naked eye. By the tenth day the embryo shows signs of life, 
and under the microscope the heart may be seen to beat. 



208 REPORT OF COMMISSIONER OF FISH AND FISHERIES. 

Following is a table showing the approximate time required for cod 
eggs to hatch, with the water at the stated mean temperatures : 



Mean water tem- 
perature. 


No. of 

days. 


Mean water tem- 
perature. 


No. of 
days. 


Mean water tem- 
perature. 


No. of 
days. 


310 F 


50 1 

31 
28 
25 


37° F 


23 
21 
19 
17 
16 
15 


43° F 


14 
13 
12 
11 
10 or 11 


32° F 


38° F 

39° F 


44° F 


33° F 


45° F 


34° V 


40° F 


46° F 


35° F 


41° F 


47° F 


36° F 


490 p 









Moderately clear water is essential to the healthy development of 
the fry. If much sediment is present it collects on the eggs and acts 
very injuriously, often killing them. Sometimes eggs become so coated 
with sediment that the fry appear to be unable to burst the shell; 
some lots of eggs thus affected have been known to retain fry fully two 
weeks beyond the normal period of incubation. 

With eggs carefully taken and fertilized, and clear water of a 
temperature from 41° to 47° F., it is possible to hatch from 70 to 85 
per cent of the eggs, but when the temperature gets below 38° the 
percentage of fry hatched is only from 25 to 50, and the average for the 
season is thus greatly reduced. The number of fry hatched is deter- 
mined by deducting the losses shown on the hatching-cards from the 
number of eggs originally in the box. One liquid ounce is estimated 
to contain 10,524 eggs. 

CLEANING THE EGGS. 

Owing to the accumulation of sediment and other foreign matters in 
the hatching-boxes, it is necessary to clean the eggs daily, running the 
sound eggs from one box to another through a slot, the dead eggs 
being left behind. The slots in the partitions dividing the hatching 
comi^artments correspond with similar slots in the boxes ; they are 3 
to 3i inches long and IJ inches deep, and are placed 3 inches from the 
front of the compartments. To begin the cleaning of a given row of 
boxes, a glass slip is fitted into the slot between the second and third 
boxes, the first box being left empty for the purpose of receiving the 
cleaned eggs from the second box. A wooden plug is then put in the 
current hole at the back of the second box, and the siphon cap is 
removed from the waste-pipe; this allows the box to fill with water, 
and the eggs, undisturbed by the current, rise to the surface. The 
water is allowed to enter the first box and to gradually fill it to the 
level of the waste-pipe, and is then turned off. A plug is next put in 
the waste-pipe of the box containing the eggs; the water rises till it 
reaches the slot, and then runs over into the first box, carrying the good 
eggs with it, while the dead eggs remain in the box. The regular water 
circulation is then established in the first box. 

The inner box from which the good eggs have been removed is taken 
out and the remaining eggs are washed into one end and poured into 



MANUAL OF FISH-CULTURE. 209 

a glass graduate. The dead eggs quickly sink and the quantity, in 
ounces, is noted on a card attached to each box. If there are any good 
eggs in the glass they are saved ; the spoiled eggs are thrown into the 
waste-trough. Both the inner box and the trough in which it rests are 
thoroughly washed and sponged after each change. 

When the inner box is replaced it is made ready for the eggs to be 
transferred from the third box, aud the same method is pursued until 
all the boxes have been cleaned. Eggs recently taken, being on the 
surface, run over very quickly, 5 or 10 minutes usually sufficing for 
the transfer of a box of 400,000 eggs; but when eggs become heavier, 
as a result of development, the cleaning takes much longer, as it is then 
necessary to run them into the lower part of the box (as in removing 
dead eggs) and to dip them out, care being taken to keep the lower 
end of the box in the water while manipulating them. As the loss of 
eggs has ceased by the time they reach this stage, everything in the 
box may be dipped over, and with care uo damage is done the eggs. 

THE FRY. 

When the fry first hatch they are much curved in shape and show 
but little vigor. If the water is comparatively warm they rapidly 
straighten out and become stronger. At this stage they float at the sur- 
face, except when forced about by the current. As they get older they 
frequent the upper water less and if kept in the boxes till the mouth 
begins to functionate most of them remain on or near the bottom. 

As soon as the first fry in a given box make their appearance the 
eggs are all rumover for the last time. As the fry are comparatively 
delicate they are handled as little as possible and with great care. 

The fry are planted as soon as practicable. If all the eggs of a given 
lot have not hatched it is better to plant them with the fry rather than 
hold the latter until incubation is complete, for the boxes soon become 
foul from the accumulation of eggshells and the eggs will haitcii in a 
very short time, especially as the water on the spawning-grounds is 
usually 3 or 4 degrees warmer than the water in the hatchery. 

When the fry are to be removed from the boxes, preparatory to plajit- 
ing, a plug is i)ut in the current hole at the back of the box, and in a 
short time most of them will come to the surface. They are then dipped 
ouifc and put in transportation cans. About 200,000 fry may be safely 
carried in a 10-gallon can. Deposits are usually made on the natural 
spawning-grounds. 

F. M. 14 



Fish Manual. (To face page 211.) 



Plate 59. 




THE MACKEREL. 



DESCRIPTION, SIZE, ETC. 

The genus Scomber, of which the mackerel {Scomber scombrus) is 
the leading representative, is distinguished from related genera of 
scombroid fishes of the Atlantic coast (Jlmx^s, the frigate mackerels; 
Gymnosarda, the little tunnies; Thunmis, the great tunnies; Sarda, the 
bonitos, and Scomber omor us, the Spanish mackerels and kingfish) by 
the small size of the species, by the absence of a median keel on each 
side of the caudal peduncle, by a short spinous dorsal fin having 9 to 
12 spines, by the pattern of coloration, and by a number of other 
characters. 

The body of the mackerel is fusiform and but little compressed later- 
ally. The standard length is 3^ times the depth. The caudal peduncle 
is slender, with a small keel on either side. One-third of the total 
length without tail consists of the head. The eye is rather small, its 
diameter being only one-fifth the length of the head. The mouth is 
large and armed with a row of small slender teeth in each jaw. There 
are two dorsal fins, the anterior containing 11 spines and the posterior 
12 rays, following which are 5 finlets ; the formula of the anal fin is 1 
spine, 11 rays, and 5 finlets. The scales are very small, numbering 
several hundred along the lateral line. The color is dark blue above 
and white below. About 35 dark wavy vertical streaks mark the back. 

The coinmon mackerel closely resembles the other species of the same 
genms found on both the Atlantic and Pacific coasts, namely, the bull's- 
eye, chub, or thimble-eye mackerel {S. colias), but is separated from it 
by the absence of the air-bladder, more dorsal spines, smaller eye, and 
somewhat different markings. 

The length of the full-grown mackerel is 17 or 18 inches, but fish a 
little over 20 inches long, and weighing upward of 3^ or 4 i^ounds, are 
occasionally taken. The average length of the market catch is about 
12 inches. Such a fish weighs from three-fourths of a pound to a i^ound. 

Small mackerel are known among the fishermen by several names, 
such as " spikes," " blinkers," and " tinkers." Spikes are the smallest 
caught by the commercial fishermen ; they are 6 or G inches long and 
are 5 to 7 months old. Tinkers are under 9 inches in length and are 
supposed to be about two years old. Blinkers are intermediate in size 
and age. Maturity is probably attained in the fourth year. 

DISTRIBUTION, MOVEMENTS, ABUNDANCE, AND SPAWNING. 

This species inhabits the North Atlantic Ocean. On the American 
coast its range is from Cape Hatteras to the Straits of Belle Isle. On 
the European coast the fish is found from northern Norway, in latitude 

211 



212 REPORT OF COMMISSIONER OF FISH AND FISHERIES. 

71°, to the Mediterranean and Adriatic. It is not recorded from the 
West Indies, Bermudas, Gulf of Mexico, South America, or Africa. 

On the east coast of North America mackerel first appear in the 
sx)ring off Cape Hatteras and subsequently reach the shores of the 
Middle and Nevr England States and the British possessions, migrating 
in from the sea from a southerly or southeasterly direction. Certain 
bodies of fish seek the New England shore, while others first strike the 
shore of Nova Scotia and follow it into the Gulf of St. Lawrence. 
They leave the coast in the same way in fall and early winter. 

The mackerel is a wandering fish. Its movements when in the coast 
waters are undoubtedly regulated by external causes not yet clearly 
understood, but food, temperature of water, and reproduction are potent 
factors. 

The mackerel is one of the most abundant fishes found on the Atlan- 
tic coast. It goes in schools, often of immense extent. The testimony 
of reliable fishermen relative to the size of schools observed often 
seems incredible; thus one school seen in the South Channel in 1848 
was half a mile wide and at least 20 miles long. Another school noticed 
off Block Island in 1877 was estimated to contain 1,000,000 barrels. The 
schools swim at the surface or at varying depths beneath the surface, 
and iiresent a comparatively broad front. 

From the earliest times, there have been periods of scarcity of mack- 
erel alternating with seasons of abundance. As early as 1G70 the 
Colony of Massachusetts enacted laws for the preservation of mackerel. 
Since 1885 there has been the most noteworthy and prolonged scarcity 
of the fish of which there is any record. The New England catch in 
1885 was 330,000 barrels, and in the 8 years ending in 1885 averaged 
309,000 barrels; in 1886 it fell to 80,000 barrels, and in the succeeding 
10 years aggregated only 481,000 barrels; was several times below 
25,000 barrels, and never exceeded 89,000 barrels. The yield in 1898 
was 5,709,000 pounds, fresh, valued at $307,000, and 15,500 barrels, 
salted^ worth $179,000. 

The spawning season on the east coast of North America includes 
the months of May, June, and July, June probably being the principal 
month. The spawning-grounds are in rather deep water and extend 
along the entire coast from Long Island to the Gulf of St. Lawrence. 
Most of the bays and sounds of the New England coast are important 
'spawning-grounds, as is also the Gulf of St. Lawrence. Prior to 
spawning and for several weeks thereafter the mackerel are lean and 
poor and never make No. 1 fish when salted. 

FOOD AND ENEMIES. 

The mackerel feeds on a large variety of small animals, and is in 
turn eaten by a number of fishes, birds, cetaceans, etc. The relations 
existing between the presence of favorite food and of enemies on one 
hand and of mackerel on the other are fully appreciated by the com- 
mercial fishermen, who are often guided in their search for fish by the 
appearance of mackerel food in abundance or of their well-known 



MANUAL OF FISH-CULTURE. 213 

enemies. The presence of food is frequently shown by flocks of birds, 
especially i^halaroi^es, which are called "mackerel geese." 

The principal food objects of the mackerel are small crustaceans; 
copepods predominate, but shrimps of various kinds, young crabs, etc., 
are also important. One of the surface-swimming copepods, known 
as "red feed," "cayenne," etc., is a very favorite food; when mackerel 
have been feeding freely on it, they spoil very quickly after being 
caught, owing to their sides rotting or "burning." Fish constitute a 
rather important part of the mackerel's diet; herring, anchovy, saud 
launce, silversides, menhaden, and many other small fishes are eaten. 

Among fishes, sharks are, perhaps, the most destructive enemies; 
mackerel sharks and dogfish are known to prey on the mackerel, 
driving and scattering the schools. Other fish enemies are bluefish 
and cod. Porpoises and whales are often seen feeding on the mackerel 
schools. Large squids do great damage to small mackerel. Among 
birds, the gannet is especially destructive. 

THE MACKEREL FISHERY. 

The mackerel is one of the best and most valuable food-fishes of the 
Atlantic Ocean. It is the object of important fisheries in Norway, 
Ireland, and Great Britain, and is extensively taken in the United 
States and the British i^rovinces of North America. The fishery is 
prosecuted with vessels using purse seines, gill nets, and lines, much 
the largest part of the catch being taken in seiues. In the boat fishery, 
lines and nets are employed. Stationary appliances, such as pound nets, 
trap nets, and weirs, also secure considerable quantities of mackerel. 

In the United States the vessel fishery is carried on chiefly from 
Gloucester, Mass. The vessels sail south in early spring, and fall in 
with the fish when they first appear off the coast of the Southern and 
Middle States, the catch being landed fresh in New York and Philadel- 
phia. The fleet next seeks the fish on the southern shore of Nova 
Scotia and follows the school north to the Gulf of St. Lawrence. 
During the summer some of the vessels enter the gulf, but most of 
them cruise on the New England shore, where most of the fall fishiug 
is also done. Some ot the finest fishing vessels of the United States 
are engaged in this fishery. In recent years the fleet has numbered 
only 150 to 225 sail, but formerly nearly 1,000 vessels were at times^^ 
employed in this branch. 

The shore and boat fishing is carried on from New Jersey to Maine* 
The fish thus caught are as a rule sold in a fresh condition. 

The fishery is much less productive than formerly, aud during the 
past ten years has not as a rule been profitable, although each year a 
few vessels make good catches and yield very satisfactory returns, 
owing to the high price of fish. The local fishing does not supply the 
home demand, and large quantities of fresh and salt mackerel are 
annually imported from Norway, Ireland, and the British provinces. 



214 REPORT OF COMMISSIONER OF FISH AND FISHERIES. 

ARTIFICIAL PROPAGATION. 

The artificial propagation of mackerel was more extensively prose- 
cuted in 1896 than in any previous year. The long-continued scarcity 
of mackerel on the Atlantic coast of the United States seemed to 
warrant some efforts on the part of the Government to increase the 
supply by artificial means. The limitations of mackerel culture depend 
oii the erratic movements of the fish in a given season or on a given 
part of the coast and the difficulty of securing healthy eggs in large 
quantities from fish taken by the commercial fishermen. During the 
summer of 1896, 24,000,000 mackerel eggs were collected. The work 
was largely experimental and only a small percentage of fry was hatched, 
but the outlook is good for a great expansion of mackerel j^ropagation. 

The egg of the mackerel is one of the smallest dealt with by the fish- 
culturist, being only 2V inch in diameter. Being j)rovided with a large 
oil-globule, it floats at the surface, like the eggs of many other marine 
fishes. Within 48 hours after fertilization it generally begins to sink, 
remains in suspension a short while, and then falls to the bottom, 
where it remains until hatching ensues. 

Owing to the inability to retain mackerel in ponds or live-cars pend- 
ing the ripening of the eggs, as is done with the cod, it is necessary to 
depend for the egg supply on the nets of the fishermen. The eggs 
collected at Woods Hole are secured from fish captured in pound nets 
near Chatham and at other jjoiuts on the southern Massachusetts coast; 
at Gloucester traps in the vicinity furnish the eggs. As the nets are 
usually hauled only once or twice a day, the fish have often been caught 
for many hours, and the tender eggs have undergone considerable loss 
of vitality; the quality of the eggs seems to have a direct relation to 
the length of time the fish have been in the nets. 

One of the most favorable grounds for collecting mackerel spawn is 
Casco Bay, on the coast of Maine. Mackerel 'are taken chiefly in drag 
nets set about 4 o'clock i). m., and hauled from 9 o'clock p. m. to day- 
light. Eggs from fish caught in the first hauls of the nets are of much 
better quality than those taken in the last lifts. 

In collecting eggs from pound nets the spawn-takers accompany the 
fishermen when they visit their nets and overhaul the mackerel as they 
are taken into the boats. The collection of eggs from the drag-net 
fishermen requires the spawn-takers to remain on the fishing-grounds 
from early in the afternoon until the next morning. 

There is nothing peculiar in the methods of stripping the fish, mixing 
the eggs and milt, and transferring the eggs from the field to the hatch- 
ery. Although both the wet and the dry methods of fertilization have 
been practiced, the latter apparently gives better results. The average 
number of eggs taken from a fish is probably about 40,000. Three 
mackerel, stripped at Woods Hole in 1893, yielded 434,500 ripe eggs, an 
average of 144,833 eggs. As many as 546,000 eggs have been taken 
from a IJ-pound fish, and the largest fish probably yield fully 1,000,000 



MANUAL OF FISH-CULTURE. 215 

eggs. The largest number of eggs takeu from one fish in Oasco Bay 
in 1897 was 200,000. 

From the fiekl the fertilized eggs are conveyed to the station in jars, 
as described in the chapter on cod propagation. For short shipments 
they may be transported in buckets or cans. 

Mackerel eggs may be artificially incubated in a variety of ways. In 
1896 three forms of apparatus were employed for comparative purposes. 
These were (1) the McDonald hatching-jar, with the water supplied 
through the long central tube and discharged through a cheese-cloth 
top; (2) the Chester jar, and (3) the automatic tidal-box; the latter 
gave the best results. 

Owing to the very small size of the eggs, from 200,000 to 225,000 
may be placed in a Chester jar and 450,000 or more in a tidal box 20 
by 11 inches. The eggs are manipulated in about the same way that 
cod eggs are, but, owing to the short period of incubation, require very 
little handling. 

For reasons not yet definitely determined, but apparently connected 
with the condition of the eggs rather than the methods of hatching, 
mackerel ova are liable to exceedingly large mortality during incuba- 
tion. While as many as 75 per cent of certain small lots of eggs have 
produced fry, less than 1 per cent of most of the eggs hatch. 

The period of incubation at a mean water-temperature of 58° is about 
5 days. In 48 hours after impregnation the embryo is discernible, and 
in 68 hours its development is far advanced. The critical period seems 
to be the end of the third day, when a large part of the eggs die. 

The fry are planted within 24 hours of hatching. They are taken 
to the natural spawning-grounds in regular transportation cans and 
liberated below the surface of the water. 



Fish Manual. (To face page 21 7. 



Plate 60. 




''^ 



XA'^?' 






THE FLATFISH, OR WINTER FLOUNDER. 



The body of the flatfisli {FsetidopJeuronectes americanus) is regularly 
elliptical. The eyes and color are on the right side. The upper side 
of the head is covered with imbricated ctenoid scales similar to those of 
the body; the blind side of the head is nearly naked. The teeth are 
close-set, incisor-like, and form a continuous cutting edge; the right side 
of each jaw is toothless. The length of the head is contained 4 times 
in the length of the body and the depth 2^ times in the body length. 
The dorsal flu contains 65 rays and the anal fin 48 rays. The lateral 
line, which is nearly straight, has 83 scales. The color above is dark 
rusty-brown, either plain or mottled with darker; the young are olive- 
brown, spotted with reddish; the under parts are white. 

This species has a comparatively small mouth, and feeds chiefly on 
small shells, crabs, and other bottom animals. It is found on sandy, 
muddy, or rocky bottoms, and seems to prefer sheltered coves and 
bays. Its coastwise and bathic movements are limited. It is one of 
the most abundant flounders of the Atlantic coast, being especially 
numerous in southern New England and New York. It ranges as far 
north as Labrador and as far south as the Carolinas, but is not present 
in noteworthy quantities south of New Jersey. It does not attain a 
large size, the usual length being only 12 to 15 inches and the weight 
about 1^ pounds. Yery rarely examples are taken over 20 inches long, 
weighing as much as 6 pounds. 

The winter flounder is exceedingly prolific, over a million eggs being 
laid by a large fish. Along the coast of the southern New England and 
Middle Atlantic States the spawning season is from February to April. 
By August the young fish, having attained a length of 1 or 2 inches, 
are found in shallow water along sandy shores. The species is obtained 
principally during the winter and spring months, and large quantities 
are sent to the markets, where it sells readily at good prices. The 
flesh is white, firm, and of excellent flavor. Next to the halibut and 
the summer flounder, or plaice {Faralichthys dentatus), this is the most 
important flatfish of the Atlantic coast. 

The winter flounder has been more extensively propagated than any 
other species of Pleuronectidcv, owing to the facility with which its eggs 
are obtained at Woods Hole, where its propagation fills in the time 
between the taking of cod eggs on one hand and of lobster eggs on the 
other, slightly overlapping the ending of the former and the beginning 
of the latter. The work covers that part of the year when the most 

217 



218 REPORT OF COMMISSIONER OF FISH AND FISHERIES. 

inclement and changeable weatber occurs, and is necessarily somewhat 
limited in extent by uncontrollable physical and other conditions. 

During the fiscal year 1895-9G, the collections of flatfish eggs num- 
bered 11,008,000, which yielded 8,472,000 fry; in the year 1896-97 
84,591,000 eggs were taken, from which 64,095,000 fry were hatched. 

The flatfish from which eggs are obtained are very plentiful during 
February in the Woods Hole region, being found on sandy or hard clay 
bottom, and taken in fyke nets set in water from 6 to 14 feet dee]}. As 
many as GO to 70 fish are sometimes taken at one lift of a fyke net, but 
as a rule not more than two or three of this number are gravid fish. 
These nets are usually some distance from the station, and the fish are 
carried to the hatchery in transportation cans, six or eight being put 
in one can. In some cases this trij:) is made by water in a sail or row 
boat, while at other times it is made overland by team. The fish are 
often carried 10 or 12 miles without change of water and without 
apparent injury. A few are caught while the water temx^erature is 
as low as 33° F., but they are more numerous after the tem])erature 
reaches 34° or 35° F. On arriving at the station the fish are \)x\t into 
wooden tanks supplied with constantly changing water, and here they 
are held until ripe. It is customary to put both males and females in 
the same box or tank. The fish are examined daily and the eggs are 
taken from all which are found to have ripened, the stripped or spent 
fish being released. 

The eggs of the flatfish are quite small, there being 30 in a linear 
inch. Unlike the eggs of the cod, haddock, mackerel, and other marine 
fishes, they do not float, but sink to the bottom of the vessel in which 
they are held. They are not so heavy as those of the lobster, and a 
slight current causes them to rise and carries them to a i)oint where there 
is still water, when they again go to the bottom. When first deposited, 
the eggs are very adhesive and stick together-in one mass or in clusters 
of different sizes. This adhesiveness is overcome, in a measure, by 
thoroughly washing them, and, as this force gradually weakens as the 
eggs become older, usually nearly all the eggs are separate when they 
begin to hatch. The use of dry powdered starch is very eflective for this 
purpose; this mixes readily with the salt water and admirably over- 
comes the glutinosity of the eggs. Its action is purely mechanical. 

In stripping, it is customary to fill a Chester jar with water and place 
inside the jar a bag made of cheese-cloth, into which the eggs are 
allowed to fall. The fish is grasped by the head with the left hand, the 
mouth being in the palm of the hand, and the edge on which the vent 
is located turned from the spawn-taker. The right grasps the fish near 
the tail, and as it is moved with gentle pressure toward the vent, at the 
same time that the left thumb is moving crosswise and exerting similar 
pressure, the eggs are extruded. The milt is then expressed in the 
same way ; the eggs are stirred- slightly with the hand to thoroughly 
mix them with the milt, and after allowing a short time for the action 



MANUAL OF FISH-CULTURE. 219 

of the milt they are cleaned and the superfluous milt washed off by 
introduciug a gentle stream of water into the bag and rolling the eggs 
from side to side. 

It frequently happens that fish held in tanks to mature deposit their 
eggs during the night. In such cases the eggs are found on the bottom 
of the tank the next morning. They are usually in clusters and when 
examined with the microscope it will be found that practically every 
egg is fertilized. 

After the eggs have been taken and fertilized the number is calcu- 
lated by measuring in a glass graduate and computing 48,726 eggs 
to the liquid ounce. The average number of eggs is about 500,000 to 
a fish. On March 6, 1897, 30 ounces, or 1 ,402,000 eggs, were taken 
from a fish 20 inches long and 11 inches wide, its weight being 3J 
pounds after the eggs were taken. 

Flatfish eggs may be hatched in several kinds of apparatus, but the 
Chester jar is most used, in combination with the McDonald tidal box 
employed in incubating cod eggs. From 400,000 to 500,000 eggs are 
usually placed in each jar. The top of the jar is covered with cheese- 
cloth held in place by rubber bands. The jar is then inverted and 
placed in a tidal box. The usual complement of each box is 2 jars. A 
wooden frame of 1-inch strips is placed lengthwise on the bottom of 
the box for the jars to rest on, so as to raise them and allow the free 
circulation of the water. A hole in the bottom of the jar allows the 
air to pass in and out as the water inside rises and falls. The inner 
compartment, with a bottom of cheese-cloth, used in cod-hatching is 
omitted. 

As in using the jars the eggs are generally on the bottom all the 
time, the experiment has been tried of employing the McDonald box 
with the automatic current in order to keep the eggs in circulation. It 
having been found that the current commonly used for cod eggs caused 
the eggs to pile up in the end nearest the outlet, a stream was intro- 
duced into each end of the box and the water was allowed to escape in 
all directions through a perforated nozzle; the water was kept about 3 
inches deep in the bottom of the box by using a quantity sufficient to 
prevent the breaking of the siphon. By this means a constant current 
is formed, the eggs develop nicely, and the fry hatch, but the current 
necessary to keep the eggs in circulation is strong enough to kill the 
fry by forcing them against the sides of the box. This experiment is 
therefore not considered a success. 

The period of incubation when the mean water temperature is 37° or 
38° F. is 17 or 18 days. 

The fry of the flatfish, although much smaller than those of the cod, 
are much more lively, and are straightened out when first hatched. 
Unlike the young cod, they do not float on the surface, but are scat- 
tered through the water from top to bottom, many being seen among 
the eggs on the bottom of the jars. Unlike the adults, the flatfish fry 



220 REPORT OF COMMISSIONER OF FISH AND FISHERIES. 

swim with the body upright, as young fish of other families do, and 
when first hatched the eyes are on opposite sides of the head. At the 
age of about three months, however, one of the eyes will have moved 
to the other side of the head, to conform with the change of the 
body in swimming from an upright to a flat position. The position 
constantly assumed by the very young fry is peculiar, the long axis of 
the body being vertical, with the head upward. This is owing to a 
large oil-globule in the anterior part of the yolk-sac. 

The fry are quite hardy and stand transportation very well. They 
have been kept three weeks without change of water in a bottle hang- 
ing in a box of running water to maintain an even temperature in the 
bottle. In planting the fry, which is done in one or two days after 
hatching, they are put into the transportation cans commonly used for 
such purposes and taken in a boat to localities in which the brood fish 
are found. The cans are put overboard and sunk until the mouth is 
submerged, when the contents are gently turned out. For a trip of not 
more than two or three hours' duration, with water temperature about 
38° F., from 400,000 to 500,000 fry may be safely carried in a 10-gallon 
can. 

THE SAND-DAB AND FOUR-SPOTTED FLOUNDER. 

Besides the flatfish or winter flounder, two other flounders have been 
artificially hatched, on a small scale, at Woods Hole; these are the 
sand-dab (Bothus macidaius) and the four-spotted ^ownAev {ParaUchthys 
oUongus). The eggs of both fish are buoyant, and deposited in May. 
Those of the former are oV inch in diameter, and of the latter .^e inch. 
The period of incubation, at a temperature varying from 51° to 54° F., 
«s about 8 days. 



Fish Manual. l_To face page 221.) 



Plate 61, 




MISCELLANEOUS MARINE FISHES. 



In addition to tlie salt-water fislies previously considered, a number of 
others liave been artificially propagated by the U. S. Fish Commission. 
With some of these the fish-cultural work has been rather extensive; 
with others, hardly more than experimental. Among those to which 
most attention has been given are tautog, Spanish mackerel, pollock, 
and haddock. Others that have come in for a share of either practical 
or experimental work are sea herring, scup, sea bass, squeteague, 
cunner, sheepshead, and several flounders. 

The same methods of culture mentioned hereafter in connection with 
tautog are applicable in general to scup, sea bass, squeteague, and other 
species having floating eggs. 

THE TAUTOG. 

The tsmtog {Tautoga onitis) is a strongly marked species. It belongs 
to a family {Labridw, or the wrasses) characterized in part by one 
dorsal fin, thoracic ventral fins, double nostrils, thick lips, and strong 
teeth in the jaws. The tautog has an elongated body and a large head 
with a convex profile. The rather small mouth is armed with strong 
conical teeth in two series. The eye is small and placed high on the 
side of the head. The body is covered with small scales, in about 60 
transverse rows and 40 longitudinal series. The head is destitute of 
scales, with the exception of a small patch behind the eye. The dorsal 
fin is long and low, with IG strong spines and 10 soft rays. The anal fin 
contains 3 spines and 8 rays. The body length is 3^ or 3 J times that of 
head and 2| or 3 times the depth. The gillrakers are short, feeble, and 
number only 9. The color of adults is almost uniformly blackish or 
greenish ; the young are marked by dark irregular crossbars on a pale 
brownish background; chin, white; iris, bright green. 

The tautog is of considerable importance in certain parts of its range. 
It is found from Maine to South Carolina, but is most abundant in 
Massachusetts, Rhode Island, and New York. It is one of the best- 
known shore fishes of the east coast, and goes by a variety of names, 
among which are blackfish, chub, oyster-fish, aiid moll, besides the 
most generally used name of tautog. 

The tautog inhabits principally rocky bottom, where it hides in crev- 
ices, often with its body in an apparently very unnatural position. It 
is quite susceptible to changes in temperature, and during winter enters 
into a state of hibernation in the more northern parts of its range. 
Its coastwise movements are very limited. Its sharp strong teeth 
enable it to consume mollusks and crustaceans, which are its chief 
food ; it also eats sand-dollars, worms, and other animals. 

221 



222 REPORT OF COMMISSIONER OF FISH AND FISHERIES. 

The tautog is takeu for market in considerable numbers by means of 
lines and traps. It bites quite readily and is a favorite with anglers. 
Its average weight as caught for sale is not more than 2 or 3 pounds, 
but tautog weighing from 6 to 15 pounds are not rare. The maximum 
weight is about 22^ pounds; such a specimen from Kew York, 36^ inches 
long, is preserved in the U. S. National Museum. Tlie annual commer- 
cial catch of tautog is about 1,000,000 pounds, valued at $25,000. Most 
of the yield is from Massachusetts, Rhode Island, and New Jersey. 

The spawning season on the southern New England coast extends 
from April to August, although June appears to be the principal mouth. 
The young are very abundant along the shores in the fall. 

The artificial j)ropagation of tautog was experimentally undertaken 
at Woods Hole in 1886. In 1896, 31,431,000 eggs were taken in June; 
from these 17,575,000 fry were hatched and xilanted in neighboring 
waters. 

Tautog from which eggs for hatching are taken are obtained from 
nets or from line fishermen near the station and transferred to live-cars. 
When first brought in they seldom yield any eggs, but in 2 to 6 hours 
they may be stripped of a part of their eggs. The eggs taken after fish 
are held more than 6 hours are usually of no value, and those obtain.ed 
from fish retained one night are invariably Avorthless. 

The tautog is very i)rolific. In 1896 a 9f -pound fish yielded 1,142,000 
eggs, and it was estimated that the ovaries contained fully as many 
more eggs that were not yet mature. The average number of eggs per 
fish is from 150,000 to 200,000. 

The eggs of the tautog are about -^V iich in diameter. They are 
buoyant, like those of the mackerel, and are susceptible of the same 
method of hatching. When placed in the automatic tidal box, they 
hatch in about 5 days, with the water temperature at 69° F., and in 2 
or 3 days with the temperature at 71°. 

The newly hatched fry are transparent and exceedingly small, the 
length being only jV inch. They are quite hardy and stand transpor- 
tation well. They are planted shortly after hatching. 

THE SPANISH MACKEREL. 

The Spanish mackerel {Scomberomorus maculatus) is the best-known 
fish of the genus and the only one that has received the attention of 
fish-culturists. From the other species of Scomberomorus found on the 
eastern United States coast {S. regalis, the kingflsh, and S. cava'ila, 
the cero) this fish is, in part, distinguished by its smaller size and by 
the insertion of the soft dorsal fin in advance of the anal. The body 
is long, the head small and pointed, the mouth large and armed with 
prominent teeth. The anterior dorsal fin has 17 spines, the soft dorsal 
has 18 rays. The anal fin has 2 spines and 17 rays. Behind both the 
dorsal and anal fins are 9 small finlets. The lateral line is wavy and 
has about 175 pores. The general color is silvery, dark-bluish above 
and whitish below. The sides have numerous rounded yellowish spots. 



MANUAL OF FISH-CULTURE. 223 

This iisli is widely distributed, being found on both coasts of North 
America. On the west coast it does not enter United States waters, 
but on the Atlantic seaboard it ranges from Texas to Massachusetts. 
It is esfjecially abundant in the Gulf of Mexico, among the Florida keys, 
in Chesapeake Bay, and on the coast of the Middle Altantic States. 

Its maximum weight is about 9 pounds. Many weighing only 1 or 
1^ pounds are caught for market, and the average is less than 3 pounds. 

The Spanish mackerel is one of the choicest food-fishes of American 
waters; in popular estimation it is scarcely surj^assed by any marine 
species except the pompano. It is caught throughout its range on the 
east coast' with gill nets, seines, pound nets, and lines. The x)rincipal 
fishing is on the west coast of Florida, on the Louisiana coast, in the 
lower part of Chesapeake Bay, and on the coasts of New Jersey and New 
York. The approximate annual value of the catch at present is $112,000, 
which represents 1,700,000 pounds. In 1880 the output was 1,887,000 
pounds, having a value of $132,000. The yield in the Middle States is 
much less than formerly, while in the Gulf States it has increased. 

The fish spawns throughout its entire range on the United States 
coast. The spawning season is quite prolonged, extending from April 
in the Carolinas to September in New York, and in a given locality 
continues from six to ten weeks. All of the eggs in the ovaries of a 
given fish do not mature at one time; eggs in all stages of development 
may be found, suggesting a comparatively long spawning season for 
individual fish as well as for the species as a whole. The eggs, when 
laid, float at the surface, where they are driven about by wind and tide. 
Doubtless a large percentage of the eggs do not hatch, through failure 
of fertilization and by being stranded. The eggs are very small, their 
diameter being only J-g- to gV of an inch. 

The artificial impregnation and hatching of Spanish mackerel eggs 
were first accomplished in 1880, since which time the propagation of 
the fish has been taken up on a number of occasions, although the 
work in any one season has been comparatively limited. 

The serious diminution in the supply of this species in certain sec- 
tions seems to call for its artificial cultivation whenever it can be taken 
up without detriment to the propagation of other more or equally 
important fish. 

In the work of artificially propagating this fish recourse has been 
had to the nets of commercial fishermen for the supply of spawn and 
milt. Chesapeake Bay has been the seat of the principal operations, 
which have been conducted by the steamer Fish Raid-. The catch of 
Spanish mackerel in this bay in pound nets and other appliances is 
very large, and the facilities for fish-cultural work of this character 
are doubtless superior to those of any other section, with the possible 
exception of the west coast of Florida. 

The necessity for depending on the fishermen for the supply of eggs 
is somewhat detrimental to the best results and prevents extensive 
■work, although the owners of fishing apparatus heartily cooperate. 



224 REPORT OF COMMISSIONER OF FISH AND FISHERIES. 

Owiug to the fact that the fish appear to spawn mostly at night, 
when the i^ound nets are lifted in the morning the ripe eggs have in 
many cases 'been extruded before the spawn-taker could secure them. 
The injuries which the fish sustain while in the pound nets and during 
the hauling of the nets appear to seriously afiect the eggs and cause 
the non-hatching of a comparatively large percentage. Undoubtedly 
better results may be obtained if a number of nets are fished exclu- 
sively for this purpose, insuring the careful removal of fish at the best 
times for taking and fertilizing the eggs. 

The eggs are very delicate and susceptible to meteorological influ- 
ences. Their development is markedly affected by water temperature 
and atmospheric conditions; electrical disturbances, as with other fish 
eggs, are injurious, but to what extent and in what way are not known. 
The largest number of ripe eggs thus far taken from a single specimen 
is 60,000, but the average is only 20,000. 

The Chester jar, such as is used in hatching flatfish eggs, has been 
found the best apparatus for Spanish mackerel eggs. If the jars are 
kept clean and not overcrowded, a constant current of water does not 
seem to be essential; of a lot of 60,000 eggs in a jar of quiet water, 90 
per cent hatched. The cod tidal-box is also adapted to this work. 

In ordinary bay water having a density of 1.014 to 1.019, the eggs 
are buoyant and remain at the surface until hatching ensues; but in 
water of low specific gravity they sink and give unsatisfactory results. 
The period of incubation is very short. Under normal conditions eggs 
hatch in 20 to 30 hours, averaging 25 hours, at a temperature of 77° 
or 78°. The fry are planted soon after hatching. 

HADDOCK, POLLOCK, AND OTHER GADID^. 

The methods of culture employed with the cod are applicable to other 
members of the cod family having buoyant eggs. The United States 
Fish Commission have frequently taken and hatched eggs of the pollock 
{Follachius virens) and the haddock {Melanogrammus (vglijinus). Both 
are important food-fishes, but much less valuable than the cod, and the 
collection of eggs has generally been only supplemental to cod work. 

The pollock is found from New Jersey northward. It goes in large 
schools, which are often found at the surface, thus differing from the 
cod and haddock. The average weight is 9 or 10 pounds, and the 
maximum about 30 pounds. Fishing is chiefly done from small vessels 
and boats, and is most important in Massachusetts. The value of the 
annual catch is about $65,000. The pollock is an excellent food-fish 
in both a fresh and a salted condition. 

The eggs of the pollock have at times been gathered in large num- 
bers in the vicinity of Gloucester; during some seasons about 40,000,000 
eggs have been taken. The eggs measure about tAj- inch in diameter. 
The pollock spawning season includes the months of October, Novem- 
ber, and December. The fish from which eggs are obtained are taken 



MANUAL OF FISH-CULTURE. 225 

with uets and lines by commercial fishermen ; the average number of 
eggs to a fish is from 200,000 to 250,000. The period of incubation is 
somewhat shorter than that of the cod, being 9 days at 43° and 6 days 
at 49°. About 5 days are required for the absorption of the yolk-sac. 

The haddock ranges from Delaware northward, and is, as a rule, very 
abundant on the "banks'- lying off the Xew England shore. In its 
habits it is similar to the cod, frequenting the same grounds and being 
caught at the same time. Its average weight is about 4 pounds and 
the maximum under 20 pounds. The fishery is very extensive in Mas- 
sachusetts, most of the catch being landed fresh in Boston. The 
annual yield is about 50,000,000 pounds, worth $850,000. 

The artificial propagation of haddock has been conducted chiefly at 
Gloucester, where as many as 30,000,000 eggs have been collected in a 
single season. The eggs are about -,\ inch in diameter, and are quite 
delicate and tender. The spawning time extends from January to 
Jnne. Tlie average production of eggs per fish is about 100,000. 

The eggs are slightly glutinous and have a tendency to form into 
small lumps during hatching. At a mean temperature of 37° they 
hatch in 15 days, and at 41° in 13 days. The yolk-sac is absorbed in 
10 days at a temperature of 41°. 

Tbe tomcod or frostfish {Microgadus tomcod) has been extensively 
propagated by the New York Fish Commission. It is a small but 
excellent food-fish, found along the Atlantic coast from New York to 
the Bay of Fundy. It is most abundant in early winter, when it 
approaches the shores and ascends streams for the purpose of spawn- 
ing. It rarely exceeds 10 or 12 inches in length. 

THE GUNNER, 

The eggs of the cunner or chogset {Gtenolabrus adspersus) are of the 
same size and character as those of its near relation, the tautog, and 
are deposited during the same season. In water having a mean tem- 
perature of 560 F. they have been hatched in 5 days, in the tidal cod-jar. 
On account of the small size, great abundance, and comparatively 
little commercial value, the propagation of the cunner has not been 
regularly undertaken. 

THE SCUP. 

The scup [Stenotomus chrysops) is a rather important small food-fish 
found along the Atlantic coast from Cape Ann to South Carolina; it is 
most abundant in southern New England. It spawns in June. The 
eggs are ,^. inch in diameter and hatch in 4 days at a mean tem- 
perature of 620 F. 

THE SEA BASS. 

The eggs of the sea bass {Gentropristes striatus) are of the same size 
as scup eggs, are deposited in June, and hatch in 5 days with the 
water temperature 59° or 60°. The sea bass is an important food-fish, 

F. M. 15 



226 REPORT OF COMMISSIONER OF FISH AND FISHERIES. 

found from Massachusetts to Florida ; it is taken in large quantities 
from New Jersey northward with lines and traps. It attains a weight 
of 5 pounds, but the average weight is only 1 or 1^ pounds. 

THE SQUETEAGUES. 

The squeteague or weakfish {Gynoscion regalis) is a prominent food- 
fish of the Atlantic and Gulf coasts, the northern limit of its range 
being in the vicinity of Cape Cod. It goes in immense schools and is 
taken in large quantities for market, 16 North Carolina, Chesapeake 
Bay, Delaware Bay, on the New Jersey and New York coasts, and in 
southern New England. It varies greatly in size; the average weight 
is under 5 pounds, but it has been known to attain a weight of 30 
pounds. In the vicinity of Woods Hole this fish spawns in June. Its 
eggs are ^g inch in diameter, and at an average temperature of 60° F. 
hatch in 2 days. 

The spotted squeteague or "sea trout" (Gynoscion nebulosum) has 
also been propagated on a small scale. It is a valuable food-fish from 
Chesapeake Bay southward, being taken in largest quantities in Vir- 
ginia, North Carolina, Florida, and the Gulf States. Its average weight 
is 2 pounds and its maximum 10 pounds. It spawns in bays and sounds 
in spring and summer, the time varying with the latitude. The eggs 
are buoyant, ;pr inch in diameter, and hatch in about 40 hours at a 
temperature of 77° F. This species has been artificially hatched on 
the southwest coast of Florida by the steamer Fish Hawk. 

THE SHEEPSHEAD. 

The sheepshead (Archosargus prohatoceplialus) is generally regarded 
as one of the best food fishes of American waters. Its deep body, of a 
grayish color, marked by 8 transverse black bauds, and its peculiarly 
shaped head, with mouth armed with prominent incisor teeth, make it 
readily recognized. It ranges from Cape Cod to Texas, but is most 
abundant from Chesapeake Bay southward. It attains a weight of 
over 20 pounds, but the average weight on the Atlantic coast is not 
over 7 or 8 pounds, and in the Gulf of Mexico scarcely exceeds 3 pounds. 
In southern waters the fish is a permanent resident, but in the northern 
part of its range it is found only during spring, summer, and autumn. 
The spawning season is from March to June, according to the locality. 

The artificial hatching of the sheepshead has been undertaken on 
several occasions, but is not regularly prosecuted. The most extensive 
work was conducted by the Fish HawJc in March and April, 188<», when 
23,400,000 eggs were taken in the vicinity of San Carlos Bay, on the 
southwest coast of Florida. These yielded 16,500,000 healthy fry, most 
of which were planted in local waters. 

In capturing spawning fish on the Florida coast it was found that 
the best time to use the seine was Just before sundown, as the flood tide 
was about to "make." The fish were then easily taken in large numbers. 
Seine hauls in the morning consisted only of male fish. Spawning 



MANUAL OF FISH-CULTURE. 227 

sheepshead swim in scliools, and seem to prefer sandy beaches, along 
whicli tbey resort at a deptli of 6 or 8 feet. 

The sheepshead egg is very small, transparent, and of less specific 
gravity than sea water. The diameter is 7^0 of an inch, and the number 
in a fluid ounce is about 50,000, or 1,600,000 in a quart. 

The eggs are satisfactorily incubated in the tidal cod-jar, about 
300,000 eggs being jdaced in each jar. The development is very rapid, 
and in the warm water of the Gulf (76° or 77° V.) the eggs hatch in 40 
hours. The newly hatched fry are very small, but active and strong, 
and withstand considerable rough handling. They are iilanted when 
72 to 80 hours old. 

It is probably not practicable to carry on extensive sheepshead 
hatching north of Florida, although small quantities of eggs could 
doubtless be taken in Korth Carolina and Virginia. 

THE SEA HERRING. 

The sea herring {Glupea Jiarengits) may be distinguished from other 
clupeoid fishes found in United States waters by the following char- 
acters: Body elongate and laterally compressed, the- depth contained 
4J times in length; numth at end of snout; lower jaw projecting, 
extending to beneath the middle of eye; roof of mouth with an ovate 
patch of small teeth; gillrakers long and slender, about 40 below 
the angle in adults, fewer in young; dorsal fin with 18 rays, inserted 
slightly behind middle of body; ventral fins beginning beueafh middle 
of dorsal; anal fin with 17 rays; median line of belly with 28 weak 
spines or scutes in front of ventral fins and 13 behind fins ; scales thin, 
easily detached, posterior edges rounded, 57 in lateral series; color 
bluish or bluish-green above, light silvery below. 

The sea herring exists in great abundance on both shores of the 
Atlantic Ocean north of the latitude of about 37*^ north. On the coast 
of North America it is not regularly abundant south of Cape Cod, but 
it is occasionally found as far south as Chesai)eake Bay. In number of 
individuals this species is probably exceeded by no other fish. On the 
Pacific Coast a similar and almost equally abundant species {Glupea 
jjallasii) is found from Alaska to jMexico. 

There are no well-defined movements of the herring on the west 
shore of the Atlantic, if those induced by the spawning instinct are 
excepted. There was formerly a distinct shoreward migration, during 
the winter months, in the Bay of Fundy, but this run has not occurred 
for a number of years. In many places the herring, especially the 
smaller individuals, appear to be resident in the shore waters. The 
maximum length of this fish is about 17 inches, and the usjual length of 
spawning fish on the United States coast is from 11 to 14 inches. 

The herring subsists on minute invertebrates, chief among which are 
copepods, larval worms, and larval mollusks. In turn it is consumed 
in enormous quantities by cod, haddock, sharks, and many other fishes. 



228 REPORT OF COMMISSIONER OF FISH AND FISHERIES. 



With res])ect to the time of spawning, the herring may be divided 
into two gronps, one spawning in the spring, in April, May, and June, 
and the other between July and December. The spring spawning 
occurs entirely east of Eastport, Maine, and the fall spawning princi- 
pally, butnot entirely, west of that place. Probably the greatest spawn- 
ing grounds south of the Gulf of St. Lawrence are at Grand Manan, 
where the eggs are deposited principally in July, August, and Septem- 
ber. Thence the season becomes progressively later westward, on the 
coast of Maine occurring between September 1 and October 15; on the 
eastern coast of Massachusetts, between October 1 and November 1, 
and south of Cape Cod from October 15 to December 1. 

The female of average size deposits between 20,000 and 47,000 eggs 
at a spawning, usually not far from 30,000. The eggs are deposited 
upon the bottom, and, being covered with a glutinous material which 
soon hardens in contact with the water, they become firmly attached 
to extraneous materials, to which they often adhere in masses as large 
as a walnut. The egg measures about oij inch in diameter, and is 
usually polyhedral from mutual pressure exerted by the eggs in masses. 

The commercial value of the sea herring is almost incalculable. It 
is undoubtedly the most important of food-fishes, although in the United 
States it is surpassed in economic value by many marine and fresh- 
water species. Some time ago the annual yield of the world was esti- 
mated at 3,000,000,000 fish, weighing 1,500,000,000 pounds, the principal 
part of which was taken in Norway. In the New England States the 
annual catch is about 70,000,000 pounds, with a first value of $600,000. 

The herring has been artificially propagated both in this country and 
in Europe, but owing to its great abundance the work has been only 
experimental. In the United States there has as yet been no perma- 
nent diminution of the supply that renders the cultivation of the species 
necessary, notwithstanding an extremely large fishery and the sacrifice 
of enormous quantities of very small fish. The first successful attempt 
to propagate this fish was in 1878, in Germany, when elaborate experi- 
ments were made. In the same year. the artificial hatching of the 
species was accomplished by the U. S. Fish Commission, The eggs, 
owing to their cohesion into masses, showed a tendency to molding, 
but this difficulty could doubtless be obviated by the use of starch, as 
with other cohesive eggs. 

Development takes place in water ranging in temperature between 
33° and 55° F., the time of incubation varying from about forty days at 
the former temperature to eleven or twelve days at the latter. Sudden 
and extreme variation between the tem])erature limits mentioned had 
little or no effect except to retard or accelerate the hatching in accord- 
ance with the rule just mentioned. When water of a temperature lower 
than 33° F. was used many of the embryos were deformed. The degree 
of salinity of the water does not appear to exert much influence upon 
the hatching of the eggs. 



1 



Fish Manual. (To face page 229 



Plate 62. 




HOMARUS AMERICANUS. Ameri'an Lobster. 



THE AMERICAN LOBSTER. 



DESCRIPTION. 



The lobster {Honiarus americanus) belongs to that group of the Crus- 
tacea called the Decapoda, because all of its members are provided with 
ten feet, more or less adapted for walking. To the Decapoda also belong 
the crabs and the shrimjis, prawns, and crayfish. The crabs are less 
related to the lobster than the other forms mentioned, and may be 
readily distinguished from them by the relatively great breadth of the 
body and the small size of the abdomen or tail, which is doubled under 
the thorax to form the " apron." The lobsters, crayfish, shrimps, etc., 
are elongate forms with the tail or abdomen very large and extended 
more or less in the same horizontal plane with the anterior part of the 
body. The lobster and the crayfishes are somewhat closely related, but 
differ, among other characters, in the number and structure of the gills 
and in the relative size of the flat.plate or scale which is attached at 
the base of the antenme or long feelers. The Pacific Coast crayfishes 
have 18 gills, those east of the Rocky Mountains have 17, while the 
lobster has 20. The appendage of the antenna is large in the cray- 
fishes, but very small in the lobster. Moreover, the crayfishes rarely 
exceed 5 or 6 inches in length, while the adult lobster is much larger, 
as seen in the markets, seldom measuring less than 9 or 10 inches. 
The spiny lobster, the ''lobster" of the Pacific Coast, is readily distin- 
guished from the crayfish and the common lobster by the total absence 
of great claws, by the greater length and stoutness of the antennae, and 
by the presence of large, broad-based, S})iuous processes on the back. 

The body of the lobster is divided into two distinct regions, the 
cephalothorax and abdomen. The former consists of the head and 
thorax fused into one united whole. That portion which would consti- 
tute the head, were it separate, bears the eyes, the two pairs of feelers, 
and the mouth, with the several pairs of modified limbs which surround 
that organ and assist in tearing up the food and passing it into the 
mouth. The thoracic portion of the cephalothorax is furnished with five 
pairs of stout limbs, the first pair bearing the great claws, which are 
rarely of the same size on the two sides, and the last four pairs Ijeing used 
in walking. From the fact that this portion of the body bears five pairs 
of appendages, it is assumed that it represents five fused segments. 

The abdomen is narrower than the cephalothorax and is composed 
of six separate segments movable on one another. In the female the 

229 



230 REPORT OF COMMISSIONER OP FISH AND FISHERIES. 

first live pairs of abdominal appendages, known as swimmerets, are all 
similar and consist of a short basal piece and two terminal pieces side 
by side. The appendages of the sixth segment consist of the same 
arrangement of parts, but the pieces are broad and paddle-like, and, 
with the terminal plate attached to the last segment, constitute a 
powerful caudal paddle or tail. In the male the abdomen is narrower 
than in the female, and the first two pairs of swimmerets differ much 
from those which follow. 

The color of the lobster is subject to great variation, but most fre- 
quently is dark bluish-green above, mottled with dark-green blotches ; 
there is usually more or less red or vermilion on the appendages, 
especially on the tubercles, tips, and under side of the great claws 
and on the antenutTe; the walking legs are light blue with reddish tips 
and tufts of hair. Occasionally specimens are found which are almost 
entirely red, and more frequently they are blue or bluish in general tone. 

DISTRIBUTION AND ABUNDANCE. 

The lobster is found from Labrador to Delaware, its range covering 
about 1,300 miles of coast line. Stragglers have been taken on the 
coasts of Virginia and North Carolina. While the bathic range is prac- 
tically limited by the 100-fathom line, it is occasionally found long 
distances from land on the fishing-banks off the New England coast. 

The lobster is most abundant in the northern part of its habitat. 
On the United States coast it is most numerous in Maine. In the 
provinces of Nova Scotia, New Brunswick, and Quebec, and also in 
Newfoundland it is extremely abundant. 

MOVEMENTS. 

The movements of the lobster are chiefly on and off shore. Such 
coastwise movements as characterize the mackerel, bluefish, and men- 
haden are never undertaken by the lobster. This fact makes possible 
the rapid depletion of fishing-grounds, and even tlie practical exter- 
mination of the lobster iu given areas; it also affords basis for the 
belief iu the efflcacy of artificial means for maintaining and increasing 
the supply. 

There are well-marked movements of the lobster induced by various 
influences, among which are the abundance or scarcity of food, the 
water temperature, and the spawning instinct. On the United States 
coast there is in the spring months a shoreward movement of large 
bodies of lobsters; 'On the approach of winter the lobsters move out 
into deep water. 

FOOD. 

The principal food of the lobster is fish, either dead or alive. Such 
bottom species as the sculpin, flounder, and sea-robin can doubtless be 
readily cauglit by the lobster, aind they also consume a large number 
of invertebrates, among them being crabs and other crustaceans, clams, 
conchs, and other mollusks, starfish, sea-urchins, etc. Lobster eggs 



MANUAL OF FISH-CULTURE. 231 

have been foiiud iu a lobster's stomach, aud algse sometimes serve as 
food. Fish is the bait most extensively employed in the lobster fishery. 

REPRODUCTION. 

The reproductive function of the lobster is not generally understood, 
and until a comparatively recent date a number of important questions 
in relation thereto were undecided. From the standpoints of tbe com- 
mercial fishermen, fish-culturist, and legislator, it is necessary that the 
principal phases of this subject be clearly appreciated, in order that 
the supply may be maintained. 

The principal spawning season for lobsters on the United States coast 
is summer, especially July and August, when probably three-fourths of 
the lobsters deposit their eggs. The remaining egg-producing lobsters 
lay during the fall and winter. A given lobster does not spawn oftener 
than every second year, as has been shown by recent studies conducted 
by the Commission. 

The eggs are fertilized outside the body of the female. The sper- 
matic fluid is deposited in a receptacle at the base of the third pair of 
walking legs, and retains its vitality for a long time. When the eggs 
are being extruded, the female lobster hes on her back and folds the 
tail so as to form a kind of chamber to retain the eggs. After their 
discharge from the body, the eggs become coated with a cement substance 
secreted by glands in the swimmerets; this substance hardens after 
being in contact with the water and firmly unites the eggs to the hair- 
like filaments on the swimmerets. The exact method by which the 
fertilizing i>rinciple is conveyed to the eggs from the pouch in which it 
is contained is not known. 

The incubative period is much prolonged. After the eggs are 
extruded and become attached externally, they are carried 10 or 11 
months before hatching ensues; during this time they are carefully 
protected, aud are perfectly aerated by the active motion of the swim- 
merets. On the United States coast most of the lobsters emerge from 
the egg in June, although some of the hatching is completed in May 
and some in July or even later, A few eggs are now known to hatch 
in winter. All of the embryos do not come from the eggs at the same 
time, the hatching occupying a week or more. The young receive no 
attention from the adults, but lead an independent existence immedi- 
ately after escaping from the egg. 

The lobster egg is about jV inch in diameter. When newly laid it is 
usually of a dark-green color, but is sometimes light-grayish or yellow- 
ish-green. 

The known maximum number of eggs produced at one time by a 
lobster is 97,410 ; the average from lobsters taken for market is 10,000 
to 12,000. The number depends largely on the size of the lobster, 
apparently in conformity to the following rule : The numbers of eggs 
laid by given lobsters vary in a geometric scale, while the lengths of 
the lobsters vary in an arithmetic scale. 



232 REPORT OF COMMISSIONER OF FISH AND FISHERIES. 

The followiug- table illustrates, with approximate accuracy, the egg- 
producing capacities of lobsters of the lengths indicated under normal 
conditions : 



Length of lobster. 


Number of 
eggs laid. 




5,000 
10, 000 
20, 000 
40, 000 
80, 000 















MOLTING AND GROWTH. 

The act of shedding the shell, or molting, is important and critical. 
It is only after shedding that growth takes place; during the early 
stages of the lobster's existence this function is often exercised in a 
comparative!}^ short time, while later it occurs only at long intervals. 
Molting in the lobster consists in throwing olf the entire external skele- 
ton, together with the lining of the digestive tract. 

The first molt takes place about the time the young emerges from 
the egg, when it is about a third of an inch long, and many lobsters 
do not survive this. During this first stage the larval lobster swims 
at or near the surface. A second molt ensues in from 1 to 5 days, and 
the lobster enters on its second stage, its average length being about 
two-fifths of an inch and its habits similar to the first stage. In 2 to 
5 days another molt takes i^lace, and the length of the larva increases 
to about half an inch. This is followed in 2 to 8 days by another molt, 
and the lobster enters on the fourth stage, when its length becomes 
slightly greater. From 10 to 20 days later the fifth molt ushers in the 
fifth stage, after which the surface-swimming habit is discarded and the 
larva goes to the bottom and begins to assume the characteristics of the 
adult. This stage lasts 11 to 18 days, and in it the young lobster has 
attained a length of about three-fifths of an inch. From this time on the 
molts are at longer and longer intervals until the fully mature condition 
is reached, when shedding takes place only once in one or two years. 

The food of lobsters during the larval stages consists chietiy of small 
crustaceans. A very pugnacious instinct then characterizes them, and 
active cannibalism prevents their artificial rearing for lack of abundant 
natural food. 

Larval lobsters are very susceptible to the influence of the sun (helio- 
tropic) while in the first three stages, being attracted by bright rays 
to the surface of the ocean or to the side of a vessel. This peculiarity 
is lost during the fourth stage. 

During the first year the young lobster, which since the fourth stage 
has become more and more like the adult in form and habits with each 
molt, attains a length of about 2 or 3 inches. At the end of the second 



MANUAL OF FISH-CULTURE. 233 

year the length, is 5 to 7 inches. By the end of 4i or 5 years a length 
of about 10 inches is reached. The rate of growth, however, depends 
greatly on the environment, the abundance of food being a very impor- 
tant factor. 

The adult lobster usually molts in summer, and in the case of the 
female, shortly after the hatching of the eggs. As several months are 
required for the new shell to acquire the hardness of the old ; as newly- 
laid eggs are rarely found on a soft-shell lobster; as molting does not 
ensue while the eggs are on the swimmerets; and, furthermore, as 
dissection has shown that the ovaries of a lobster whose eggs have 
recently hatched are in an immature condition and will not yield eggs 
until the succeeding year, it follows that the mature lobster deposits 
eggs not oftener than once in two years, with an alternating molt. 

SIZE AND ^^^IGHT. 

The average size of lobsters caught for market is now much less than 
it was in the earlier days of the fishery, and their avefage weight is 
probably not over 2 pounds. A lobster 9 inches long weighs, on an 
average, 1^ pounds; a lOi-inch lobster, l^ pounds; a 12-inch lobster, 3 
pounds; and a 15-inch lobster, 4 to 5 pounds; while a lobster 20 inches 
long weighs 20 pounds or more. Lobsters weighing as much as 15 or 
20 pounds are uncommon, and those weighing over 20 pounds are very 
rare. Up to a recent date, the largest lobster of authenticated weight 
■wat about 25 pounds. In 1897, however, 3 lobsters, each weighing over 
30 pounds, were taken off Sandy Hook, N. J.,the weight of the largest 
being 33 pounds. 

The male lobster weighs more than the female of the same length, 
the difference in 11-inch lobsters, for instance, being about a quarter 
of a pound. 

The size at which the lobster attains sexual maturity is a very 
important question. In the jSTew England and Middle States and the 
Canadian Provinces the laws relating to the minimum size of market- 
able lobsters are (juite various and illustrate the absence of definite 
information on tliis subject. In Maine, Massachusetts, New Hamp- 
shire, and New York the minimum limit of size of lobsters that maybe 
sold is now lOi inches; in Rhode Island it is 10 inches, and in Con- 
necticut it is 9 inches. In the British Provinces the limit is much 
lower than in Maine. 

Investigations conducted by the Fish Commission on the NewEngland 
coast show that the female lobster attains maturity when from 8 to 12 
inches long. Comparatively few lobsters under 9 inches in length 
lay eggs. Of over 1,000 egg-bearing lobsters collected at Woods Hole 
during a period of years, less than 2 per cent were under 9 inches long. 
On the other hand, by the time they have reached the length of lOi 
inches most lobsters will have produced eggs, and this should be the 
minimum size permitted in the markets. 



234 REPORT OF COMMISSIONER OF FISH AND FISHERIES. 



COMMERCIAL VALUE. 



^i 



The lobster is tbe most important crustacean of the United States. 
It is the object of a special fishery, carried on with pots or traps, in all 
the coastal States from Delaware northward, and ulso in Xova Scotia, 
New Brunswick, Prince Edward Island, Quebec, and Newfoundland. 
In Maine, where the fishery is more important than in any other State, 
the lobster is the j)rincipal fishery product. Over 4,500 persons are 
engaged in this fishery in tlie United States; the capital invested is 
about $875,000, and tlie catch in 1890 amounted to 15,121,000 pounds, 
valued at $1,319,000. In 1880 the yield was larger (20,240,000 pounds), 
but the market value was much less, being only $488,000. 

Between 1889 and 1899 the New England lobster catch decreased over 
15,000,000 pounds, or 50 per cent, while the value increased more than 
$400,000, or 50 per cent. For a number of years this fishery presented 
the anomaly of a diminishing supply and an angmented catch, owing 
to the more active prosecution of the business; but the decline in the 
yield has for some time been unchecked, notwithstanding the employ- 
ment of more apparatus and the prolongation of the fishing season. 
With a singular disregard for their own welfare, many fishermen have 
continually violated the State laws for the protection of small, imma- 
ture lobsters and females bearing eggs. Only the rigid enforcement of 
restrictive measures by the States and the extensive artificial propaga- 
tion of the lobster can ward off the destruction which threatens this 
valuable fishery. 

INCEPTION AND PROGRESS OF LOBSTER-CULTURE. 

If egg-bearing lobsters were not liable to destruction by man, arti- 
ficial propagation would hardly be necessary. Notwithstanding the 
enactment of stringent laws prohibiting the sale of '• berried " lobsters, 
the frequent sacrifice of such lobsters, with their eggs, and of many 
immature lobsters, has seriously reduced the lobster output and rendered 
active and stringent measures imperative. By the present methods 
millions of lobster eggs are annually taken and hatched that would be 
lost, and the females producing them, amounting to several thousands, 
are liberated. 

Prior to 1885 experiments had been conducted at various points look- 
ing to the artificial propagation of the lobster. The only practical 
attempts of this nature previous to those made by the Fish Commission 
were bj^ means of " parking," that is, holding in large naturally inclosed 
basins lobsters that had been injured, soft-shelled ones, and those below 
marketable size. Occasionally female lobsters with spawn were placed 
in the same inclosures. One of these parks was established in Massa- 
chusetts in 1872, but was afterward abandoned ; another was established 
on the coast of Maine about 1875. It was soon demonstrated, however, 
that the results from inclosures of this character, so far as the rearing 
of the lobsters from the young were concerned, would not be sufficient 
to materially affect the general supply. 



Fish Manual. (To face page 234) 



Plate 63. 




LABORATORY, HATCHERY, AQUARIUM, AND MUSEUM, U. S. FISH COMMISSION, WOODS HOLE, MASS. 




RESIDENCE, U. S. FISH COMMISSION, WOODS HOLE, MASS. 



MANUAL OF FISH-CULTURE. 235 

The completion of the new marine laboratory and hatchery at Woods 
Hole in 1885, with its complete system of salt-water circulation, j)er- 
mitted the commencement of experiments in artificial hatching on a 
large scale, which had not been practicable theretofore, although small 
quantities of lobster eggs, as well as those of other crustaceans, had 
been successfully hatched. In 1886 the experiments had progressed so 
successfully that several million eggs were collected and hatched at 
Woods Hole, the fry being deposited in Vineyard Sound and adjacent 
waters. From 1887 to 1890, inclusive, the number of eggs collected 
was 17,821,000. 

From the eggs collected up to 1889 the average production of fry was 
about 51 per cent. During these years experiments were conducted as 
to the best method of hatching the eggs. The various forms of appa- 
ratus used were the Chester jar, the McDonald tidal box, and the 
McDonald automatic hatching-jar. In 1889 the results secured in the 
latter form of apparatus were so much better than with the others that 
it was adopted, and in 1890, from the 4,353,000 eggs collected, over 81 
per cent yielded fry. Work was continued at Woods Hole on about 
the same scale until 1894, when the collections aggregated 97,000,000 
eggs. In the same year lobster propagation was undertaken at G-.louces- 
ter and a collection of 10,000,000 eggs was made there. 

During the fiscal year 189i> the number of eggs taken by the Fish 
Commission was 105,188,000, the resulting fry liberated numbering 
97,579,000, or about 93 per cent; and in 1897 the collections amounted 
to 133,562,000 eggs, of which 115,606,000, or 90 per cent, were hatched. 

COLLECTION OF EOa-BEARING LOBSTERS. 

Although the new eggs appear on the lobsters during the months of 
July and August, no special eflbrt is made to secure egg bearing 
lobsters until the following spring. The collections usually commence 
in April and continue until the middle of July. At Woods Hole it 
has been the recent practice to receive at the station and place in the 
hatching-jars during the fall and winter any lobsters having external 
eggs that may be captured by local fishermen. The collecting-grounds 
extend from Xew London, Connecticut, to the eastern end of Maine. 
For W^oods Hole station eggs are secured from fishermen operating 
between New London, Connecticut, and Plymouth, Massachusetts. 

The most important grounds in Connecticut are in the vicinity of New 
London and Noank; in Massachusetts, New Bedford, South Dartmouth, 
Plymouth, Woods Hole, and numerous localities in Buzzards Bay and 
Vineyard Sound. Eggs for the Gloucester station are secured from the 
fishermen operating between Boston and Rockland, which territory 
comprises the most important lobster fishery in the United States. The 
schooner Gramims is used in making the collections between Portland 
and Rockland, the lobsters being delivered at Gloucester early in the 
season and later on to the steamer Fish Hawk, which is stationed at a 
suitable point in Casco Bay. 



236 REPORT OF COMMISSIONER OF FISH AND FISHERIES. 

As the laws of Massachusetts, ISTew Hampshire, and Maiue prohibit 
the holding of the "berried" libsters by the fishermen, arrangements 
are made with the State authorities by which certain ofiicials of the Fish 
Commission are appointed deputy wardens and authorized to hold egg- 
bearing lobsters for fish-cultural purposes in live-boxes. Early in the 
spring all of the lobster fishermen in the territory referred to above are 
visited by agents of the Commission, who arrange with them to hold 
all of their egg lobsters in live-cars until called for, at a price agreed on. 

Collections are made from Woods Hole and Gloucester by steam 
launches and sailing vessels. The steam launches visit the near points 
three to four times a week to obtain egg-bearing lobsters. The vessels 
collect at more distant points in Connecticut and Maine. Local agents 
at Boston and Plymouth, Massachusetts, and Kittery Point, Maine, 
also collect egg-bearing lobsters, which are held in live-boxes until the 
agent has a sufficient number to make a trip. On the arrival of the 
vessel or launch at the station the lobsters are transferred to tanks 
supplied with running water and held until the spawn-taker is ready to 
strip the eggs. 

TAKING AND MEASURING THE EGGS. 

The receptacle into which the spawn-taker strips the eggs from a 
lobster is either a glass jar (9 inches in diameter) or a water-bucket, 
which, after thorough cleaning, is parti}' filled with water. 

The operator, with his left hand, grasps the lobster from above and 
turns it on its back, lowering it into the spawning- vessel head down- 
ward. By pressing it firmly against the sides of the jar it is prevented 
from using the anterior part of its body or its mandibles. The hand is 
then slipped farther back toward the tail and the segmented portion of 
the body is held firmly to prevent its closing. The lobster is then ready 
for stripping. A rather dull, short-bladed knife is used to separate 
the eggs from the swimmerets, to which they are attached by hair-like 
fibers; stripping begins at the last pair of swimmerets and gradually 
proceeds toward the body. As the eggs are scraped off they fall into 
the water m the jar. Some which adhere to the claws of the lobster 
are washed off by means of a small stream of water. The lobster is 
then put back into a tank, where it remains until liberated. 

Lobsters received by the local agents at Boston and Kittery Point 
are held until a suitable quantity is on hand and are then stripped, the 
eggs being taken to the station in transportation cans and the adnlts 
released. Early in the spring the eggs stand transportation well, but 
late in the season, as incubation becomes more advanced, they are very 
delicate and are quickly affected by rough handling or sudden changes 
in temperature. 

Before being transferred to the hatching-vessels the eggs are accu- 
rately measured, generally with a glass graduate, into which they are 
poured, the water being drawn off. The basis of measure is an ounce, 
which contains about 6,090 eggs. 



MANUAL OF FISH-CULTURE. 237 

HATCHING APPARATUS AND OPERATIONS. 

Experiments conducted during a series of years having demonstrated 
that the automatic hatching-jar was the best form of apparatus for 
hatching lobster eggs, it has been adopted at the stations of the Cora- 
mission since 1889. A full description of this jar is given in the article 
on shad-culture, pj). 150-152. The manipulation and operation of the jar 
is practically the same as with shad eggs, except that frequently, where 
the water supply is inadequate, three jars are connected by means of 
rubber tubing and the water used over and over. This is accomplished 
by connecting the overflow from the first jar with the supply to the 
second and so on, but can only be done during the early stages before 
the fry commence to hatch. When first placed in the jar the eggs are 
matted together by the fine hair-like fibers, but after a few days they 
separate and work very much like shad eggs. 

From 400,000 to 500,000 eggs (equivalent to about 2 to 2^ quarts) are 
usually placed in each jar, although at times when the hatchery is 
crowded a few more may be successfully cared for. 

The fry pass voluntarily from these jars to cylindrical glass jars, 9 
inches in diameter and either 9 or 18 inches high, placed in the center 
of the table and covered with cheese-cloth at the top to prevent their 
escape. 

The period of incubation depends entirely upon the age of the egg 
when collected. For example, eggs taken in October do not hatch until 
the following May, whereas eggs collected in June frequently hatch 
in 24 hours after being placed in the jars. During one season eggs 
collected from December 12 to January 25, numbering 1,717,000, at a 
temperature of 45°, commenced hatching May 25 at a temperature of 
54°. To determine how soon the new-laid eggs can be taken from the 
parent and hatched artificially, collections were begun early in July 
and continued until fall, for several seasons, the eggs being placed in 
hatching-jars at the Woods Hole Station; all those collected prior to 
October 15 died. In November, 1895, 15,000,000 were placed in jars 
and carried through the winter under very unfavorable conditions, but 
hatched with a loss of only 50 per cent. The density of the water at 
Woods Hole varies from 1.023 to 1.025, its average temperature being 
from 49° to 04° during the months of April, May, and June. 

THE LOBSTER FRY. 

Owing to the cannibalistic habits of young lobsters when closely 
crowded, it has been the policy of the Commission to liberate the fry 
as soon after hatching as possible. They are taken out in ordinary 
10-gallon transportation cans, about 200,000 being placed in a can for 
shortshipments and 125,000 for long shipments, and liberated in the 
vicinity of the grounds from which the adult lobsters were taken. 
When this is impracticable, they are liberated in Vineyard Sound and 
Buzzards Bay with an outgoing tide, so as to insure their wide distri- 



238 REPORT OF COMMISSIONER OF FISH AND FISHERIES. 

bution. The question of the transportation of lobster fry any great 
distance is still an unsettled one, as in but few instances has it been 
attem])ted to ship them by rail, and then the trips were comparatively 
short — namely, from Woods Hole to Cold Spring Harbor, New York; 
fi'om Woods Hole to Provincetown and Plymouth, and from Grioucester 
to Kittery Point. The shipments from Woods Hole have all been very 
successful, and there seems little doubt that the young lobster will 
stand transportation for 24 hours with excellent results. 



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